Rotation detecting device and wheel support bearing assembly utilizing the same

ABSTRACT

To provide a rotation detecting device with a function of transmitting a rotational speed detection signal wireless and enable the rotation detecting device to be assembled compact in size without requiring any anti-rusting treatment to a multi-pole magnet assembly and a magnetic ring assembly, the rotation detecting device includes an electric power generator ( 11 ) for generating an electric power by a relative rotation between a non-rotatable member ( 1 ) and a rotatable member ( 7 ). The electric power generator ( 11 ) includes a multi-pole magnet assembly ( 13 ) and a magnetic ring assembly ( 12 ). A wireless transmission device ( 14 ) for transmitting the rotational speed detection signal outputted by the electric power generator ( 11 ) is employed. A sealing member ( 18 ) is also employed for sealing a working space delimited between the non-rotatable member ( 1 ) and the rotatable member ( 7 ), and the multi-pole magnet assembly ( 13 ) and the magnetic ring assembly ( 12 ) of the electric power generator ( 11 ) confront with each other at a location inwardly of the sealing member ( 18 ). The sealing member ( 18 ) is mounted on the magnetic ring assembly ( 12 ) or the wireless transmission device ( 14 ) of an annular configuration.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a rotation detecting device fordetecting the number of revolutions of a rotating element such as awheel and for transmitting wireless an electric signal indicative of thedetected number of revolutions. The present invention also relates to awheel support bearing assembly utilizing the rotation detecting devicereferred to above and to a rolling bearing assembly equipped with anelectric power generator that provides an electric power source or thelike for the rotation detecting device of the type referred to above.The rolling bearing assembly equipped with the electric power generatorcan find a variety of applications such as in a wheel support bearingassembly provided with a wireless sensor and an ABS system.

2. Description of the Prior Art

A rotation detecting device for detecting the number of revolutions, orthe rotational speed for short, that is equipped with an electric powergenerator and a wireless transmission unit has been well known in whichthe electric power generator includes a magnetic ring assemblyaccommodating a coil and a multi-pole magnet assembly. In this electricpower generator employed in the known rotation detecting device, themagnetic ring assembly is mounted fixedly on one of rotatable andnon-rotatable members while the multi-pole magnet assembly is mountedfixedly on the other of the rotatable and non-rotatable members, so thata relative rotation of those rotatable and non-rotatable members canresult in generation of an electric power. An output signal indicativeof the rotational speed, which is generated from the electric powergenerator, is transmitted wireless by the wireless transmission unit.

The electric power generator referred to above is disposed betweenpluralities of raceways defined in the non-rotatable and rotatablemembers, respectively, with the multi-pole magnet assembly and themagnetic ring assembly disposed between the pluralities of suchraceways. Also, a sealing member for sealing a working space delimitedbetween the non-rotatable and rotatable members is integrated togetherwith the multi-pole magnet assembly, while the structure may also beavailable in which the multi-pole magnet assembly and the magnetic ringassembly are positioned externally of the seals.

In the electric power generator in which the multi-pole magnet assemblyand the magnetic ring assembly are disposed externally of the seals, themulti-pole magnet assembly is exposed to foreign matter such as salinedirt and grits and, therefore, an anti-rusting treatment is requiredwhere the multi-pole magnet assembly makes use of magnets such asrare-earth magnets that are susceptible to rusting. Also, where themagnetic ring assembly is also susceptible to saline dirt and grits, theanti-rusting treatment has to be applied to the magnetic ring assembly.The anti-rusting treatment to be applied to the magnets and the magneticring assembly includes a plating process, in which zinc or nickel isplated on surfaces of the magnets and the magnetic ring assembly, apainting process in which an anti-rusting paint is applied to surfacesof the magnets and the magnetic ring assembly, and a resin moldingprocess in which the magnets and the magnetic ring assembly are coveredwith a resin material.

When the anti-rusting treatment against the saline dirt and grits isemployed, the plated or painted layer must have a relatively large filmthickness. In particular, where the resin molding process is used, theresultant resin layer has a film thickness generally greater than theplated or painted layer. Accordingly, if the anti-rusting treatment isapplied to the magnets and the magnetic ring assembly, particularly torespective surfaces of the magnetic ring assembly and the magnets thatconfront with each other, a gap between the magnets and the magneticring assembly would undesirably increase enough to lower the electricpower output generated by the electric power generator. Although theproblem associated with reduction in electric power output of theelectric power generator would be resolved if the number of turns of thecoil accommodated in the magnetic ring assembly is increased and/or themagnets of a relatively large thickness are employed, any of thosemeasures would result in an undesirable increase of the size of theelectric power generator.

Also, if foreign matter enter between the respective surfaces of themagnetic ring assembly and the magnets that confront with each other,those surfaces would be scratched or otherwise damaged in contact withthe foreign matter and the anti-rusting film or mold would then beimpaired enough to allow rusting to occur in those surfaces. Because ofthis, additional seals would be required to avoid ingress of the foreignmatter.

One example of the rolling bearing assembly equipped with the electricpower generator of the kind discussed above is currently available andis shown in FIG. 38A. Referring to FIG. 38A, the rolling bearingassembly 71 includes an inner race 72 defining the non-rotatable memberand an outer race 73 defining the rotatable member. An electric powergenerator 76 used therein includes a stator 74, i.e., a magnetic ringassembly mounted on one end of the inner race 72, and a rotor 75, i.e.,a multi-pole magnet assembly mounted on an adjacent end of the outerrace 73, and generates a rotational speed detection signal indicative ofthe number of revolutions of the outer race 73 in terms of the electricpower generated thereby. In such structure, an electric circuit unit 77is provided at a location outwardly of one end of the inner race 72defining the non-rotatable member, so as to extend axially outwardlyfrom the position where the multi-pole magnet assembly 75 is disposed.In the example now under discussion, this electric circuit unit 77includes an electric circuit substrate 79 encased within, for example, ametallic protective casing 78 as shown in FIG. 38B and having variouselectric component parts necessary to form a signal processing circuit,an electric power source circuit, a transmission circuit and others. Thecoil 80 in the magnetic ring assembly 74 and the electric circuit unit77 are electrically connected with each other by means of an electricwiring 81. According to the conventional example shown in FIGS. 38A and38B, the electric power generated by the electric power generator 76 isutilized not only as the rotational speed detection signal, but also asan electric power source for electrically powering the signal processingcircuit and the transmission circuit through an electric power sourcecircuit, and the rotational speed detection signal is subsequentlytransmitted wireless from a transmitting antenna 82 of the transmissioncircuit to an external receiver circuit.

However, with the above discussed conventional rolling bearing assemblyof the type equipped with the electric power generator, the electriccircuit unit 77 including the electric power source circuit, theprocessing circuit for processing the rotational speed detection signal,the transmission circuit and others is necessarily disposed at alocation distant and separate from the electric power generator 76,hence involving a problem associated with complication in structure.Also, a complicated procedure is required to electrically connect thecoil 80 in the magnetic ring assembly 74 and the electric circuit unit77 together through the electric wiring 81. Considering that the coil 80makes use of a relatively thin electric wire, a terminal treatment isrequired to lead the electric wire out from the coil 80, resulting asubstantial amount of manual intervention. In addition, a measure toavoid any possible breakage of joints in the electric wiring 81 and aprotective casing 78 for protecting the electric circuit unit 77 fromexternal environment are needed and does therefore provide a cumbersomeaddition to the complicated structure and the complicated assemblage.

Furthermore, an anti-skid braking system (ABS) is known, which operatesto detect the onset of a wheel skid, which would be likely to occur whenthe wheel rotates on a low friction ground surface or is abruptlybraked, and then to loosen the braking to thereby maintain tire grip tosecure a steering control. A rotational speed sensor for detecting theonset of the wheel skid is generally disposed in the wheel supportbearing assembly. This sensor has a sensing portion disposed inface-to-face relation with a pulsar ring mounted on, for example, oneend of a raceway member positioned externally of the bearing assembly.However, since the pulser ring and the sensing portion are exposed tothe outside, a problem would often occur in that reduction in size ofthe wheel support bearing assembly tends to be hampered. In order toalleviate such problem, wheel support bearing assemblies have beensuggested in which an electric power generator that serves as arotational speed sensor for providing an output signal indicative of thenumber of revolutions of the wheel is employed and in which, as shown inFIG. 39, arrangement is made to transmit the rotational speed detectionsignal wireless.

Referring now to FIG. 39, the wheel support bearing assembly showntherein makes use of an electric power generator 86 of a structure inwhich a multi-pole magnet assembly 85 is mounted on an inner member 82of the bearing assembly and a magnetic ring assembly 84 is mounted on anouter member 83 so as to confront the multi-pole magnet assembly 85 in adirection radially of the bearing assembly, so that a relative rotationbetween the inner and outer members 82 and 83 can result in generationof an electric power. The inner member 82 is arranged inside the outermember 83 through a plurality of circumferential rows of rollingelements 88. A coil is disposed within the magnetic ring assembly 84.This magnetic ring assembly 84 is fixed to an inner peripheral surfaceof a ring-shaped mounting member 89 mounted on the outer member 83,while the multi-pole magnet assembly 85 is mounted on an outerperipheral surface of a ring-shaped mounting member 90 mounted on theinner member 82. The mounting member 90 is a member concurrently servingas a core metal for the multi-pole magnet assembly 85. The mountingmember 89 on which the magnetic ring assembly 84 is fixed is providedwith a wireless transmission device 87 for transmitting wireless therotational speed detection signal, represented by the electric poweroutput generated by the electric power generator 86, through atransmitting antenna of the wireless transmission device 87 to theoutside of the wheel support bearing assembly in the form of a radiowave for use in anti-skid control performed by the automobile anti-skidbraking system (ABS). The mounting member 90 referred to above is amember that defines a core metal for the multi-pole magnet assembly 85and includes a portion that defines a slinger 90 a cooperable with asealing member 91. The outer member 83 is operatively coupled with aknuckle 92, while the inner member 82 is operatively coupled with anouter race 93 of a constant velocity universal joint.

However, with the rolling bearing assembly equipped with the electricpower generator of the structure discussed above, since the mountingmembers 89 and 90 are mounted respectively on the outer and innermembers 82 and 83 of the bearing assembly and the magnetic ring assembly84 and the multi-pole magnet assembly 85 are in turn mounted on themounting members 89 and 90, respectively, a relatively large number ofcomponents are required. Also, the magnetic ring assembly 84 is requiredto be incorporated in the mounting member 89 with no gap formedtherebetween to avoid the possibility that the magnetic ring assembly 84may separate from the mounting member 89 under the influence ofvibrations, resulting in complicated assemblage. Also, in order tosecure a gap between the magnetic ring assembly 84 and the multi-polemagnet assembly 85 confronting the magnetic ring assembly 84, themounting members 89 and 90 need to be exactly aligned coaxially witheach other. For this reason, the mounting members 89 and 90 have to beprecisely machined, resulting in increase of the cost. Yet, since evenin this example, the electric power generator 86 and the wirelesstransmission device 87 are positioned at respective locations separatefrom each other, the wheel support bearing assembly of the structureshown in and described with reference to FIG. 39 has problems similar tothose involved in the wheel support bearing assembly of FIGS. 38A and38B.

Also, in the wheel support bearing assembly of the structure discussedabove, in view of the relation in position with a wheel and a tirehousing, the inboard side is in an environment exposed to saline dirtand grits splashed from the ground surface and, therefore, forprotection of the raceways within the bearing assembly and, also, theelectric power generator 86, a reliable and firm sealing performance isrequired.

However, in the wheel support bearing assembly of the structure shown inand discussed with reference to FIG. 39, the sealing member 91 isinterposed between the mounting members 89 and 90 and, therefore, nocontact pressure would be secured in the sealing member 91 due to anerror in positioning of the mounting members 89 and 90 relative to eachother, resulting in a risk of incomplete sealing. For this reason, inorder for the positioning error to be compensated for, the sealingmember 91 must have an increased sectional surface area, but theincreased sectional surface area cannot often be secured in the sealingmember 91 in view of the relation in position thereof relative to theperipheral component parts such as the knuckle 92, the outer race 93 ofthe constant velocity universal joint and others. Also, in the face of apressing demand for compactization of the wheel support bearingassembly, the space delimited between the knuckle 92 and the outer race93 of the constant velocity universal joint is extremely small. Yet, inview of the presence of the peripheral component parts, the sectionalsurface area of the electric power generator 86 cannot be increased and,therefore, it is generally difficult to secure the electric power thatcan be generated.

If the sealing member 91 is disposed directly between the outer andinner members 83 and 82 such as found in the standard wheel supportbearing assembly having no electric power generator incorporatedtherein, the sealing performance could be secured, but the electricpower generator 86 would be positioned outside the sealing member,resulting in addition of one or more extra sealing member.

It is also suggested to dispose the slinger 90 a, cooperable with thesealing member 91, on the outer race 93 of the constant velocityuniversal joint to thereby increase the space for installation of theelectric power generator 86 and, also, the space for installation of thesealing member 91, but it is difficult to secure a sufficient space forinstallation of the electric power generator 86 after all. Depending onthe size of the electric power generator 86 and that of the sealingmember 91, the cup portion of the outer race 93 of the constant velocityuniversal joint would be incapable of securing a required wallthickness. Where the wireless transmission device 87 is employed, thespace for installation thereof is additionally limited.

SUMMARY OF THE INVENTION

In view of the foregoing, one object of the present invention is toprovide a rotation detecting device compact in structure and having afunction of transmitting wireless a rotational speed detection signal,but utilizing a multi-pole magnet assembly and a magnetic ring assemblyboth requiring no anti-rusting treatment, and also to provide a wheelsupport bearing assembly.

Another object of the present invention is to provide a rolling bearingassembly equipped with an electric power generator, that is simple instructure and can easily be assembled.

A further object of the present invention is to provide a rollingbearing assembly equipped with an electric power generator, in which theelectric power generator can easily and accurately be incorporated witha minimized number of component parts.

A still further object of the present invention is to provide a wheelsupport bearing assembly equipped with an electric power generator, inwhich a sufficient space for installation of the electric powergenerator can be secured and a freedom of design choice can beavailable.

In order to accomplish these objects of the present invention, inaccordance with a first aspect of the present invention, there isprovided a rotation detecting device which includes a rotatable memberrotatably supported on a non-rotatable member; an electric powergenerator for generating an electric power by a relative rotationbetween the non-rotatable member and the rotatable member; atransmission device of an annular configuration for transmittingwireless at least one of a rotational speed detection signal outputtedby the electric power generator and an output signal from a sensor thatoperates using as an electric power source the electric power generatedby the electric power generator; and a sealing member for sealing aspace delimited between the non-rotatable member and the rotatablemember. The electric power generator referred to above includes amulti-pole magnet assembly having a plurality of alternating magneticpoles arranged in a circumferential direction, and a magnetic ringassembly accommodating a coil and confronting the multi-pole magnetassembly. The wireless transmission device used therein is disposedaxially outwardly, but adjacent the magnetic ring assembly of theelectric power generator, while the sealing member is mounted on thewireless transmission device and has a lip member slidingly engaged witha seal contact area defined in the rotatable member. The magnetic ringassembly and the multi-pole magnet assembly of the electric powergenerator confront with each other at a location inwardly of the sealingmember.

Where the wireless transmission device is made up of a wirelesstransmitter and members used to support it, that portion which definesthe wireless transmitter is positioned axially outwardly, but adjacentthe magnetic ring assembly. The non-rotatable and rotatable membersreferred to above may be those positioned radially outwardly andinwardly relative to each other, respectively. The multi-pole magnetassembly and the magnetic ring assembly may be so disposed as toconfront with each other in an axial direction or a radial direction ofthe bearing assembly.

In the rotation detecting device according to a second aspect of thepresent invention, the wireless transmission device referred to above isintegrated together with, for example, the magnetic ring assembly of theelectric power generator. The term “integrated together” hereinabove andhereinafter referred to is intended to mean that the wirelesstransmission device and the magnetic ring assembly can be treated as asingle unitary component.

Also, in the rotation detecting device according to a third aspect ofthe present invention, instead of the transmission device and themagnetic ring assembly being integrated together, the annular wirelesstransmission device is mounted on the non-rotatable member and thesealing member is mounted on the wireless transmission device thenmounted on the non-rotatable member. Where the wireless transmissiondevice is integrated together with the electric power generator ormounted on the non-rotatable member, the wireless transmission device ispreferably disposed axially outwardly of the magnetic ring assembly ofthe electric power generator, but it may not be always disposed axiallyoutwardly thereof.

In the rotation detecting device according to a fourth aspect of thepresent invention, instead of the magnetic ring assembly being mountedon the wireless transmission device, the sealing member is mounted onthe magnetic ring assembly of the electric power generator. Even in thiscase, sealing lips of the sealing member are held in sliding contactwith the seal contact area defined in the rotatable member and themagnetic ring assembly and the multi-pole magnet assembly of theelectric power generator are held in face-to-face relation at a locationinwardly of the sealing member.

According to the first to fourth aspects of the present invention, sincea portion where the magnetic ring assembly and the multi-pole magnetassembly confront with each other is positioned inwardly of the sealingmember to thereby avoid any possible ingress of saline dirt and grits,there is no need to apply the anti-rusting treatment to the magnet andthe magnetic ring assembly to avoid the possible ingress of saline dirtand grits. Because of this, the multi-pole magnet assembly can beinexpensively assembled and the gap between the magnetic ring assemblyand the multi-pole magnet assembly of the electric power generator canalso be minimized, resulting in compactization of the electric powergenerator. Also, formation of the magnetic ring assembly by the use of asteel material having a high magnetic permeability and no rust proofmakes it possible for the electric power generator to be furthercompactized. Also, since there is no need to mount the sealing member onthe non-rotatable member, there is no need to provide the non-rotatablemember with a seal mount and, therefore, the non-rotatable member canhave a reduced size. For these reasons, the space for installation ofthe electric power generator and the transmission device can be expandedadvantageously.

Where the wireless transmission device is assembled in a ring form andthe sealing member is mounted on this ring-shaped wireless transmissiondevice, there is no need to provide a sectional shape of the magneticring assembly of the electric power generator with surface projectionsor recesses necessary to engage with the sealing member and, therefore,the sealing member while simplifying the magnetic ring assembly in shapecan easily be mounted on the wireless transmission device. Because ofthis, the magnetic ring assembly can have a reduced magnetic path and,hence, a reduced magnetic resistance. As a result thereof, theefficiency of electric power generation increases, allowing the electricpower generator to be assembled further compact in size. On the otherhand, where the annular wireless transmission device is mounted on themagnetic ring assembly to thereby integrate it together with the latter,the coaxial alignment between the non-rotatable and rotatable memberscan be improved, with the sealing performance consequently increased. Itis, however, to be noted that the sealing member may not be alwaysmounted directly on the wireless transmission device, but where anymember is, for example, used for mounting the wireless transmissiondevice on the non-rotatable member or for mounting it on the magneticring assembly of the electric generator, the sealing member may bemounted on such member.

Also, the distance of spacing between the multi-pole magnet assembly andthe magnetic ring assembly can be reduced and material of a highmagnetic permeability can be used for the magnetic ring assembly tothereby increase the efficiency of electric power generation.

In the rotation detecting device according to any one of the first tofourth aspects of the present invention, the wireless transmissiondevice may have an inner peripheral surface formed with a to-be-engagedportion comprised of a projection or a recess and the sealing member maybe formed with an engaging portion comprised of a recess or a projectionengageable with the to-be-engaged portion on the inner peripheralsurface of the wireless transmission device, so that the sealing membercan be mounted inside the wireless transmission device with the engagingportion engaged with the to-be-engaged portion. Where the sealing memberis mounted on the magnetic ring assembly of the electric powergenerator, the inner peripheral surface of the magnetic ring assembly isformed with a to-be-engaged portion comprised of a projection or arecess, so that the to-be-engaged portion can be engaged with theengaging portion formed in the sealing member. It is to be noted thatthe to-be-engaged portion and the engaging portion may be defined so asto extend over the entire circumference or may be defined at a singlelocation or a plurality of discrete locations on the circumference.

The provision of the to-be-engaged portion and the engaging portion inthe manner described above is effective to avoid any possible separationof the sealing member from the wireless transmission device or themagnetic ring assembly whichever the sealing member is mounted on. Theto-be-engaged portion and the engaging portion may be of a respectivekind having a minimized resistance with a relative movement forengagement and having a relatively large resistance with a relativemovement for disengagement or drawing our, such as, for example, detentpawls.

A rolling bearing assembly equipped with an electric power generatoraccording to a fifth aspect of the present invention may include firstand second members rotatable relative to each other through rollingelements, an electric power generator capable of generating an electricpower by a relative rotation between the first and second members, andan electric circuit disposed within a yoke, forming a part of theelectric power generator, and utilizing the electric power generated bythe electric power generator.

According to the fifth aspect of the present invention, since theelectric circuit is disposed inside the yoke, there is no need to mountthe electric circuit externally of the bearing assembly. A protectivecasing which is required when the electric circuit is mounted externallyof the bearing assembly is not needed and, therefore, compactization isadvantageously possible. Also, connection between the coil of theelectric power generator and the electric circuit can easily beaccomplished. For these reasons, the structure can be simplified andassemblage can be accomplished easily. A wire used to form the coil canbe directly connected with a circuit substrate of the electric circuitand, in such case, no treatment of a wiring terminal is needed. Since anelectric wiring to be led out can be drawn from the circuit substrate,the wiring can easily be accomplished.

If the electric circuit referred to above is provided with a rectifiercircuit appropriate to characteristics of the electric power generatorand an output protective circuit and is then mounted in the yoke, anelectric power generator unit capable of being used as a stable electricpower source can be obtained.

In the rolling bearing assembly equipped with the electric powergenerator according to the foregoing fifth aspect of the presentinvention, the first and second members rotatable relative to each othermay be, for example, inner and outer members, respectively.

The electric power generator referred to above may include themulti-pole magnet assembly having a plurality of alternating magneticpoles arranged in a circumferential direction, and a magnetic ringassembly accommodating a coil therein and defining a yoke confrontingthe multi-pole magnet assembly, wherein the multi-pole magnet assemblyis mounted on one of the inner and outer members while the magnetic ringassembly is mounted on the other of the inner and outer members.

The use of the multi-pole magnet assembly facilitates an accuratedetection of the rotational speed and also permits the electric power tobe generated efficiently with a compact structure.

In the fifth aspect of the present invention, the rolling bearingassembly equipped with an electric power generator may include awireless transmission device for transmitting wireless at least one of arotational speed detection signal outputted by the electric powergenerator and an output signal from a sensor that operates using as anelectric power source the electric power generated by the electric powergenerator. The electric circuit disposed in the yoke has to include oneof a rectifier circuit for rectifying a generated electric current, asignal processing circuit and a transmitter circuit of the wirelesstransmission device.

This design feature is effective to allow the rotational speed detectionsignal detected to be transmitted wireless to the outside of the bearingassembly with no possibility of breaking of wire while eliminating theneed to use an extra electric power source of the wireless transmission.

Also, in the fifth aspect of the present invention, the electric circuitsubstrate mounting the electric circuit referred to above may be mountedon a coil bobbin included in the electric power generator. With theelectric circuit substrate mounted on the coil bobbin, an electricconnection between an electric power generator coil and the electriccircuit can easily be accomplished.

Yet, in the fifth aspect of the present invention, the electric circuitsubstrate mounting the electric circuit may be a part of the coil bobbinof the electric power generator. If the electric circuit substrate andthe coil bobbin are thus integrated together in this way, the axialdimension of the electric power generator can be reduced, making itpossible for the electric power generator to be assembled compact insize.

Considering that the wheel support bearing assembly is used under asevere environment such as exposed to a ground surface and, accordingly,if a wiring is employed for outputting the rotational speed detectionsignal from the rotation detecting device and also for connection withthe electric power source, a problem often occurs which is associatedwith breakage of the wiring. A water proofing treatment against dirt andgrits is also required. Because of these, while the rolling bearingassembly equipped with the electric power generator according to thepresent invention has a structure easy to assemble and compact in size,an advantage of having the capability of generating the electric powergenerating capability can be effectively demonstrated.

A rolling bearing assembly equipped with an electric power generatoraccording to a sixth aspect of the present invention may include theinner and outer members rotatable relative to each other through therolling elements, and the electric power generator having the multi-polemagnet assembly mounted on one of the inner and outer members and havinga plurality of alternating magnetic poles arranged in a circumferentialdirection and also having the magnetic ring assembly mounted on theother of the inner and outer members and accommodating a coil andconfronting the multi-pole magnet assembly. The magnetic ring assemblyincludes a stepped portion made up of a peripheral surface portion andan end face portion and defined on an outer periphery or an innerperiphery of one end thereof. This magnetic ring assembly is mounted onthe other of the inner and outer members by press-fitting the peripheralsurface portion of the stepped portion directly onto a peripheralsurface of the other of the inner and outer members within a bearingspace between the inner and outer members. The peripheral surface withinthe bearing space is an inner peripheral surface in the case of theouter member and an outer peripheral surface in the case of the innermember.

According to this sixth aspect of the present invention, since themagnetic ring assembly is provided with the stepped portion and ismounted on one of the outer and inner members directly underinterference fit, no fixing member is necessary and the number ofcomponent parts used can advantageously be reduced. Also, since theperipheral surface within the bearing space in any one of the outer andinner members of the bearing assembly is precisely machined, themagnetic ring assembly can be precisely fitted and a gap can easily besecured between the magnetic ring assembly and the multi-pole magnetassembly. In addition, by causing the end face portion of the steppedportion of the magnetic ring assembly to be engaged with the end face ofone of the outer and inner members, the magnetic ring assembly can beaxially properly positioned. The magnetic ring assembly is mountedneither on the outer member nor the inner member in its entirety, butonly an axial portion thereof is mounted and, therefore, a sufficientsectional dimension can be secured even though the bearing space isnarrow.

In this sixth aspect of the present invention, the magnetic ringassembly may be made up of a plurality of divided ring membersconfronting in an axial direction. In such case, the divided ringmembers are connected together with respective portions in section alongthe axial direction being capped one over the other, and the connectingstrength with which the respective portions of the divided ring membersare connected with each other can increase as the magnetic ring assemblyundergoes deformation upon press-fitting thereof on the other of theinner and outer members.

The use of the magnetic ring assembly of a divided structure facilitatesmounting of the coil within the magnetic ring assembly. On the otherhand, the divided structure often constitutes a cause of increase of amagnetic resistance in a joint between the divided ring members.However, since the divided ring members are so designed as to becombined together with the respective portions in section along theaxial direction being capped one over the other, so that the connectingstrength with which the respective portions of the divided ring memberscan be connected with each other can increase as the magnetic ringassembly undergoes deformation upon press-fitting thereof on the inneror outer member, the magnetic resistance in the magnetic circuit definedin the magnetic ring assembly does not increase, permitting the electricpower generated to be secured satisfactorily.

The magnetic ring assembly referred to above may have a seal mount of astepped or recess configuration defined at a portion on one sideopposite to the stepped portion in the axial direction, and a sealingmember may be mounted on the seal mount for sealing a working spacedelimited between the inner and outer members.

Utilization of the magnetic ring assembly as a seal mount facilitatesassemblage of the sealing member. Also, since no extra member isnecessary to define the seal mount, any undesirable increase in numberof the component parts can be eliminated advantageously. Also, since themagnetic ring assembly can be precisely mounted owing to the engagementof the stepped portion as described above, the positioning accuracy ofthe seal member on the magnetic ring assembly can be increased and thesealing performance can easily be secured.

Instead of the outer surface of the magnetic ring assembly used as aseal mount, the magnetic ring assembly may include a mounting ringprotruding outwardly from an end face opposite to the stepped portion ofthe magnetic ring assembly in the axial direction so as to define a sealmount, and the sealing member may be mounted on the mounting ring forsealing a working space delimited between the inner and outer members.

Even when the mounting ring is provided in the magnetic ring assembly asdescribed above, incorporation of the sealing member can easily beaccomplished. Although the use of the mounting ring results in increaseof the number of component parts, a recessed portion that defines theseal mount is not needed in the magnetic ring assembly and, accordingly,the magnetic ring assembly can have a simplified shape. Also, if themounting ring is beforehand mounted in the magnetic ring assembly, themounting ring and the magnetic ring assembly can advantageously behandled as a single unitary structure during assemblage of the bearingassembly.

Where the mounting ring is used in the magnetic ring assembly, themagnetic ring assembly may be mounted on the outer member whereas themounting ring is mounted on an outer periphery of the magnetic ringassembly with a portion engaged with an outer peripheral surface of theouter member.

Where the mounting ring is employed, the mounting ring can be utilizedto fix the sealing member and the wireless transmission device and, atthe same time, to prevent the magnetic ring assembly from being axiallyseparated. In such case, the mounting ring can have a function ofprotecting the magnetic ring assembly from dirt and grits. Although dueto the above reason an anti-rusting treatment is required, it isseparate from the magnetic circuit and, therefore, a non-magneticmaterial can advantageously be employed therefor. Also, with thisstructure, the magnetic ring assembly may be made of a material havingno resistance to corrosion but a high magnetic permeability, resultingin increase of the efficiency of electric power generation.

Also, in the sixth aspect of the present invention, the rolling bearingassembly equipped with the electric power generator may further includethe wireless transmission device of an annular configuration fortransmitting wireless one of a rotational speed detection signaloutputted by the electric power generator and an output from a sensorthat utilizes the electric power generator as an electric power source,and the wireless transmission device may be mounted on the magnetic ringassembly.

The provision of the wireless transmission device can simplify a wiringsystem and, therefore, the problem associated with breakage of thewiring can be eliminated advantageously. If the wireless transmissiondevice is of an annular configuration and is then mounted on themagnetic ring assembly, the wireless transmission device will not undulyprotrude outwardly and the bearing assembly as a whole can have acompact contour.

Where the mounting ring is used on the magnetic ring assembly, thewireless transmission device may be of an annular configuration and maybe mounted on an peripheral surface of the mounting ring opposite to adifferent peripheral surface thereof defining the seal mount.

If one surface of the mounting ring is used as a seal mount and theother surface thereof is used to support the wireless transmissiondevice, the sealing member and the wireless transmission device can bearranged compact in size.

The rolling bearing assembly equipped with the electric power generatorin the practice of the present invention may be a wheel support bearingassembly. In other words, the rolling bearing assembly equipped with theelectric power generator according to the sixth aspect of the presentinvention may be of a structure in which the outer member has an innerperipheral surface formed with inner raceways and the inner member hasan outer peripheral surface formed with outer raceways confronting theinner raceways, with the rolling elements received in part in the innerraceways and in part in the outer raceways, so that the rolling bearingassembly can be used to rotatably support a wheel relative to anautomobile body structure.

The wheel support bearing assembly is desired to be equipped with anelectric power generator so that it can be used as a highly intelligent,high performance bearing assembly for detection of the rotational speedof the wheel for control by an anti-skid braking system or for any otherpurpose. However, demands for accuracy, assemblability and reduction inweight are severe and, therefore, the advantage of the present inventionin which with a minimized number of component parts the electric powergenerator can be accurately and easily incorporated in the rollingbearing assembly can be effectively available.

According to a seventh aspect of the present invention, there isprovided a wheel support bearing assembly equipped with the electricpower generator, which assembly includes the outer member connected withan automobile body structure through a knuckle and having a plurality ofthe outer raceways defined in an inner peripheral surface thereof; theinner member having a corresponding number of the inner raceways definedin an outer peripheral surface thereof in alignment with the respectiveouter raceway in the outer member; a corresponding number of rows of therolling elements rollingly accommodated in part within the innerraceways and in part within the outer raceways, respectively; and theelectric power generator including the multi-pole magnet assemblymounted on the inner member and having a plurality of alternatingmagnetic poles defined therein in a circumferential direction thereof,and the magnetic ring assembly accommodating a coil and confronting themulti-pole magnet assembly. The magnetic ring assembly referred to aboveis mounted on the knuckle.

With the above discussed structure, since the magnetic ring assembly ofthe electric power generator is mounted on the knuckle, the spacebetween the constant velocity universal joint and the knuckle can beeffectively utilized as a space for installation of the electric powergenerator. Because of this, without a problem with the capacity beinginvolved, the electric power generator can be mounted on an inboard endof the bearing assembly where the space is limitted and, therefore, afreedom of design choice can be appreciated.

In this seventh aspect of the present invention, the end face of theouter member on the inboard side may be axially inwardly set back from aplane flush with the end face of the inner member to define a set-backspace in which the magnetic ring assembly of the electric powergenerator may be disposed. Where the magnetic ring assembly is mountedon the knuckle and the sealing member is mounted on the magnetic ringassembly, no sealing member needs mounted on the inner peripheralsurface of the outer member and, therefore, the end face of the outermember can be set back as discussed above. By so doing, the amount ofmaterial for the outer member can advantageously be reduced, resultingin an inexpensive bearing assembly. Also, by a quantity corresponding tothe set-back space so defined in the outer member, the space fordisposition of the electric power generator and the sealing member canbe increased, resulting in a relatively greater freedom of designchoice.

In the seventh aspect of the present invention, a slinger may beprovided axially outwardly of the multi-pole magnet assembly on theinner member, and the sealing member is then mounted on the magneticring assembly and slidingly engageable with the slinger while anon-contact seal is defined between each free end of the slinger and thesealing member.

When the slinger and the sealing members are so arranged as to slidinglyengage with each other at a location axially outwardly of the bearingassembly relative to the multi-pole magnet assembly, that portion atwhich the multi-pole magnet assembly and the magnetic ring assemblyconfront with each other can be located radially inwardly of the sealingmember and, therefore, any possible ingress and subsequent biting ofdirt and grits onto a surface of the multi-pole magnet assembly canadvantageously be avoided. The sealing member referred to above canserve for sealing the interior of the bearing assembly and also forprotecting the surface of the multi-pole magnet assembly and, therefore,unlike the case in which a dedicated sealing member is employed for theelectric power generator, the surface of the multi-pole magnet assemblycan be assuredly protected. Also, since the sealing member cooperateswith the slinger to define the non-contact seal between it and the freeend of the slinger, a dual sealing effect can be obtained by the lipseal and the non-contact seal, resulting in a high performance seal. Forthis reason, a preventive performance to avoid any possible ingress ofsaline dirt and grits from the outside into the interior of the bearingassembly can advantageously be increased. Since the sealing member ismounted on the magnetic ring assembly, no extra member for mounting isneeded and the efficiency of utilization of the space is high. Becauseof those features, the space hitherto used to accommodate the sealingmember and the space available between the outer peripheral surface ofthe outer race of the constant velocity universal joint and the innerperipheral surface of the knuckle can be utilized for accommodating theelectric power generator and the sealing member as desired, resulting inan increased freedom of design choice.

Where the multi-pole magnet assembly makes use of a metal core, theslinger may be an integral part of the core metal forming a part of themulti-pole magnet assembly. The integration of the core metal and theslinger results in reduction in number of the component parts and alsothat of manufacturing steps and, therefore, the wheel support bearingassembly can be manufactured inexpensively.

Also, the inner member may be fitted with the outer race of the constantvelocity universal joint, or the outer race of the constant velocityuniversal joint may be used as an element forming the inner member, inwhich case the multi-pole magnet assembly may be mounted on the outerrace of the constant velocity universal joint. The mounting of themulti-pole magnet assembly on the outer race of the constant velocityuniversal joint eliminates the necessity of a margin required in theinner member for the multi-pole magnet assembly to be mounted and,therefore, that portion which function as a bearing assembly can becompactized.

Yet, a support plate may be employed which is adapted to be fitted tothe knuckle by means of a bolt used to secure the outer member to theknuckle. This support plate may have a cylindrical portion definedtherein, and the magnetic ring assembly may then be fitted within aninner periphery of the cylindrical portion of the support plate.

Where the use is made of the support plate and the magnetic ringassembly is fitted inside the support plate, the magnetic ring assemblycan easily be fitted inside the support plate by, for example, anengagement. Also, since the support plate is fitted by means of the boltused to secure the outer member to the knuckle, the support plate can befitted simultaneously when the outer member is secured to the knuckle.Therefore, no extra procedure for bolting solely the support plate iseliminated and, accordingly, the mounting of the magnetic ring assemblyonto the knuckle can easily be accomplished.

Where the support plate is employed as described above, the supportplate may have a flange extending radially inwardly beyond the innerperipheral surface of the outer member, and a sealing plate may bepositioned axially inwardly of the radially inwardly extending flangeand spaced a slight distance therefrom to define a labyrinth sealbetween the radially inwardly extending flange and the sealing plate.

Formation of the labyrinth seal in this way is effective to avoid apossible leakage of a lubricant such as a grease filled in the bearingassembly. Since the radially inwardly extending flange which is a partof the support plate is utilized, the labyrinth seal can be formedadvantageously with a minimized number of component parts.

Also, where the support plate is employed as described above, a portionadjacent an opening of an inner peripheral surface of the knuckleadjacent an area where the support plate is secured may represent agenerally stepped cylindrical surface flaring outwardly and thecylindrical portion of the support plate may be formed as a steppedcylinder engageable around the stepped cylindrical surface of theknuckle. An axial gap can then be defined between an annular step in thestepped cylindrical surface of the knuckle and an annular step in thecylindrical portion of the support plate representing a steppedcylindrical shape, and an elastic seal member can be disposed withinsuch axial gap.

Intervention of the elastic seal in the axial gap between the annularstep in the stepped cylindrical surface of the knuckle and the annularstep in the cylindrical portion of the support plate is effective toensure a firm sealing achieved between the knuckle and the supportplate.

Again, where the support plate is employed as described above, a resinlayer may be employed for sealing a gap defined between the portionadjacent the opening of the inner peripheral surface of the knuckleadjacent the area where the support plate is secured and an outerperipheral surface of the cylindrical portion of the support plate. Thisresin layer may be provided on the outer peripheral surface of thesupport plate.

The use of the resin layer is effective to achieve a seal between theknuckle and the support plate with no need to use any elastic sealelement such as an O-ring. Accordingly, the number of component partscan be reduced and assemblage can be accomplished easily.

In the practice of the seventh aspect of the present invention, a sensorwhich operates using the electric power generated by the electric powergenerator as an electric power source may be provided in the wheelsupport bearing assembly. This sensor may be of a type used to detectrotation or to detect a parameter other than rotation, such asvibrations and/or temperature. Since the electric power generated by theelectric power generator is used as an electric power source therefor,no wiring is routed, thereby simplifying the wiring system.

Also, in any of the various aspects of the present invention, the wheelsupport bearing assembly may have the transmission device fortransmitting wireless at least one of a rotational speed detectionsignal outputted by the electric power generator and an output signalgenerated from the sensor that operates using the electric power of theelectric power generator as an electric power source. This transmissiondevice may be disposed in the vicinity of the magnetic ring assembly.

The provision of the wireless transmission device is effective toeliminate any use of a wiring used for electric connection between thewheel support bearing assembly and the automobile body structure. Also,since the electric power generator provides an electric power source forthe rotation detection and also for the sensor, it is possible toeliminate the use of an electric power source wiring. For this reason,while the wheel support bearing assembly is of a type capable ofdetection, any complicated wiring job can be eliminated and assemblageinto the automobile body structure can easily be accomplished. Althoughthe use of the wireless transmission device requires a space forinstallation thereof, the fact that the magnetic ring assembly of theelectric power generator is mounted on the knuckle provides a relativelygreat freedom of design choice with respect to the space availablebetween the knuckle and the outer race of the constant velocityuniversal joint and, accordingly, the space for installation of thewireless transmission device can easily be available.

BRIEF DESCRIPTION OF THE DRAWINGS

In any event, the present invention will become more clearly understoodfrom the following description of preferred embodiments thereof, whentaken in conjunction with the accompanying drawings. However, theembodiments and the drawings are given only for the purpose ofillustration and explanation, and are not to be taken as limiting thescope of the present invention in any way whatsoever, which scope is tobe determined by the appended claims. In the accompanying drawings, likereference numerals are used to denote like parts throughout the severalviews, and:

FIG. 1 is a longitudinal sectional view of a wheel support bearingassembly according to a first preferred embodiment of the presentinvention

FIG. 2 is a fragmentary longitudinal sectional view, on an enlargedscale, of the wheel support bearing assembly of FIG. 1, showing thedetails of a rotation detecting device used therein;

FIG. 3 is a fragmentary longitudinal sectional view, on a furtherenlarged scale, of the rotation detecting device of FIG. 2;

FIG. 4A illustrates a ring forming a part of an electric power generatorused in the wheel support bearing assembly of FIG. 1, which ring isshown in part in a side sectional view and in part in a side view;

FIG. 4B is an end view of the ring shown in FIG. 4A;

FIG. 5 is a fragmentary longitudinal sectional view showing the detailsof the rotation detecting device employed according to a secondpreferred embodiment of the present invention;

FIG. 6 is a fragmentary longitudinal sectional view showing the detailsof the rotation detecting device employed according to a third preferredembodiment of the present invention;

FIG. 7 is a fragmentary longitudinal sectional view showing the detailsof the rotation detecting device employed according to a fourthpreferred embodiment of the present invention;

FIG. 8 is a fragmentary longitudinal sectional view showing the detailsof the rotation detecting device employed according to a fifth preferredembodiment of the present invention;

FIG. 9 is a fragmentary longitudinal sectional view showing the detailsof the rotation detecting device employed according to a sixth preferredembodiment of the present invention;

FIG. 10 is a fragmentary longitudinal sectional view showing the detailsof the rotation detecting device employed according to a seventhpreferred embodiment of the present invention;

FIG. 11 is a fragmentary longitudinal sectional view showing the detailsof the rotation detecting device employed according to an eighthpreferred embodiment of the present invention;

FIG. 12 is a fragmentary longitudinal sectional view, on an enlargedscale, showing the electric power generator employed in the wheelsupport bearing assembly according to a ninth preferred embodiment ofthe present invention;

FIG. 13 is a fragmentary side sectional view showing the relationship inposition between a component of the magnetic ring assembly and a coilbobbin;

FIG. 14 is a fragmentary side sectional view showing a portion of themagnetic ring assembly on an enlarged scale;

FIGS. 15A and 15B are plan views showing different examples of anelectric circuit substrate used in the electric power generator,respectively;

FIG. 16 is a circuit block diagram showing the electric power generatorand an electric circuit employed in the electric power generator;

FIG. 17 is an electric circuit diagram showing an example of an electricpower source circuit used in the electric circuit shown in FIG. 16;

FIGS. 18A and 18B are explanatory diagrams showing the electric powersource circuit in charge and discharge modes, respectively;

FIG. 19 is a sectional view showing an example of the structure in whichthe electric circuit is mounted on the coil bobbin;

FIG. 20 is a sectional view showing another example of the structure inwhich the electric circuit is mounted on the coil bobbin;

FIG. 21A is a sectional view showing a further example of the structurein which the electric circuit is mounted on the coil bobbin;

FIG. 21B is a fragmentary elevational view showing a further example ofthe structure in which the electric circuit is mounted on the coilbobbin;

FIG. 22A is a sectional view showing a still further example of thestructure in which the electric circuit is mounted on the coil bobbin;

FIG. 22B is a fragmentary elevational view showing a still furtherexample of the structure in which the electric circuit is mounted on thecoil bobbin;

FIG. 23 is a sectional view showing a still further example of thestructure in which the electric circuit is mounted on the coil bobbin;

FIG. 24 is a sectional view showing a still further example of thestructure in which the electric circuit is mounted on the coil bobbin;

FIG. 25 is a fragmentary sectional view showing a still further exampleof the structure in which the electric circuit is mounted on the coilbobbin;

FIG. 26 is a longitudinal sectional view of a wheel support bearingassembly equipped with the electric power generator according to a tenthpreferred embodiment of the present invention;

FIG. 27 is a longitudinal sectional view, on an enlarged scale, showinga portion of the wheel support bearing assembly shown in FIG. 26;

FIG. 28 is a fragmentary longitudinal sectional view, on a furtherenlarged scale, showing the details of mounting of the electric powergenerator in the wheel support bearing assembly;

FIG. 29 is a fragmentary longitudinal sectional view, on an enlargedscale, showing the wheel support bearing assembly according to aneleventh preferred embodiment of the present invention;

FIG. 30 is a fragmentary longitudinal sectional view, on an enlargedscale, showing the wheel support bearing assembly according to a twelfthpreferred embodiment of the present invention;

FIG. 31 is a fragmentary longitudinal sectional view, on an enlargedscale, showing that portion of the wheel support bearing assemblyaccording to a thirteenth preferred embodiment of the present invention;

FIG. 32 is a fragmentary longitudinal sectional view, on an enlargedscale, showing the wheel support bearing assembly according to afourteenth preferred embodiment of the present invention;

FIG. 33 is a fragmentary longitudinal sectional view, on an enlargedscale, showing the wheel support bearing assembly according to afifteenth preferred embodiment of the present invention;

FIG. 34 is a fragmentary longitudinal sectional view, on an enlargedscale, showing the wheel support bearing assembly according to asixteenth preferred embodiment of the present invention;

FIG. 35 is a fragmentary longitudinal sectional view, on an enlargedscale, showing the wheel support bearing assembly according to aseventeenth preferred embodiment of the present invention;

FIG. 36 is a fragmentary longitudinal sectional view, on an enlargedscale, showing the wheel support bearing assembly according to aneighteenth preferred embodiment of the present invention;

FIG. 37 is a fragmentary longitudinal sectional view, on an enlargedscale, showing the wheel support bearing assembly according to anineteenth preferred embodiment of the present invention;

FIG. 38A is a longitudinal sectional view of the conventional wheelsupport bearing assembly;

FIG. 38B is a sectional view showing the details of an electric circuitemployed in the conventional wheel support bearing assembly of FIG. 38A;and

FIG. 39 is a sectional view of the different conventional wheel supportbearing assembly.

DETAILED DESCRIPTION OF THE EMBODIMENTS

FIG. 1 is a drawing of a wheel support bearing assembly of a typeequipped with a rotation detecting device, which drawing is commonlyused in describing the preferred embodiments of the present inventionaccording to first to sixth aspects thereof. The wheel support bearingassembly shown therein includes a non-rotatable or stationary member 1made up of a generally cylindrical outer member 2 and a knuckle 10 fixedto, for example, an automobile body structure or chassis. The outermember 2 is coupled with the knuckle 10 through a flange 2 a thatprotrudes radially outwardly from the outer member 2. The wheel supportbearing assembly also includes a rotatable member 7 made up of agenerally cylindrical inner member 3 and an outer race 15 a of aconstant velocity universal joint 15 secured to an inner peripheralsurface of the inner member 3. The outer member 2 has its innerperipheral surface formed with a plurality of, for example, two, axiallyspaced outer raceways 5 a and 5 b and, correspondingly, the inner member3 has its outer peripheral surface formed with axially spaced innerraceways 6 a and 6 b aligned respectively with the raceways 5 a and 5 b.

The inner member 3 includes a hub wheel 3 a and an inner race formingmember 3 b, and the inner raceways 6 a and 6 b referred to above are, sofar as in the illustrated embodiment, defined in the hub wheel 3 a andthe inner race forming member 3 b, respectively.

Rolling elements 4 arranged in circumferentially extending rows areaccommodated within an annular working space defined between the outerand inner members 2 and 3 and are received in part within the outerraceways 5 a and 5 b and in part within the inner raceways 6 a and 6 b,respectively, to permit the inner member 3 to rotate relative to theouter member 2. As a matter of design, the rolling elements 4 of eachcircumferential row are retained in position by a retainer or cage 8. Assuch, the outer member 2, the inner member 3, the rolling elements 4 andthe associated retainers 8 altogether constitute a rolling bearingassembly with the outer and inner members 2 and 3 defining outer andinner raceways. An outboard open end of the annular working spacebetween the outer and inner members 2 and 3, that is adjacent the flange3 a, is sealed by a sealing member 9.

It is to be noted that the inner member 3 referred to above may not bealways limited to the structure described, but may be of any suitablestructure. By way of example, the inner member 3 may be of a structuremade up of two raceway defining members for each row of the rollingelements 4 and a hub wheel, or of a structure formed integrally with theouter race 15 a of the constant velocity universal joint 15 with atleast one raceway defined on the outer race 15 a for the rollingelements 4.

An electric power generator is generally identified by 11 and includes agenerally cylindrical magnetic ring assembly 12 made of a magneticmaterial and having a coil built therein, and a multi-pole magnetassembly 13 positioned radially inwardly of the magnetic ring assembly12 in face-to-face relation. This magnetic ring assembly 12 has itsouter peripheral surface formed with a reduced diameter portion and alarge diameter portion with a shoulder defined between the reduced andlarge diameter portions thereof and is carried by the outer member 2with the reduced diameter portion of such magnetic ring assembly 12fitted inside the inner peripheral surface of the outer member 2. Inother words, the magnetic ring assembly 12 has one end portion fitted tothe inner peripheral surface of the outer member 2. In the illustratedembodiment, the magnetic ring assembly 12 defines a stator of theelectric power generator 11. On the other hand, the multi-pole magnetassembly 13 is magnetized to have a plurality of alternating magneticpoles spaced an equal distance from each other in a directioncircumferentially thereof. This multi-pole magnet assembly 13 is fixedlymounted on the inner member 3 and, in the illustrated embodiment,defines a rotor of the electric power generator 11.

Referring now to FIGS. 4A and 4B, the magnetic ring assembly 12 is madeup of two divided ferromagnetic ring members 30 a and 30 b held axiallyin face-to-face relation with each other. The ferromagnetic ring members30 a and 30 b are each in the form of an annular member having such asectional shape as best shown in FIG. 4B and are engaged with each otherat their respective outermost peripheral portions 35 and 36. The firstand second ferromagnetic ring members 30 a and 30 b have respectiveannular side walls 32 and 33 extending radially inwardly therefrom, andthese annular side walls 32 and 33 are each formed with a plurality ofclaws 31 a and 31 b that are bent to protrude towards the opposed sidewalls 33 and 32 in a direction axially of the magnetic ring assembly 12.In an assembled condition of the magnetic ring assembly 12, the claws 31a integral with the first ferromagnetic ring member 30 a and the claws31 b integral with the second ferromagnetic ring member 30 b areinterleaved with each other in a direction circumferentially of themagnetic ring assembly 12 with a predetermined space defined between theneighboring claws 31 a and 31 b. With the claws 31 a and 31 binterleaved with each other to represent a generally comb-shape andspaced a predetermined distance radially from the multi-pole magnetassembly 13, a so-called claw-pole type electric power generator is thusdefined. It is to be noted that material for each of the ferromagneticring members 30 a and 30 b is preferably chosen to be a magneticmaterial having a resistance to rusting such as ferrite stainless steel,particularly that identified by SUS 430 according to the JapaneseIndustrial Standards (JIS).

The magnetic ring assembly 12 has a hollow defined between the first andsecond ferromagnetic ring members 30 a and 30 b and also has a coil (notshown) accommodated within such hollow. The coil within the hollow ofthe magnetic ring assembly 12 is retained in position by an elasticmaterial 29 such as an elastic bonding material that fills up thehollow. This elastic material 29 serves not only to provide an electricinsulation between the magnetic ring assembly 12 and the coil, but alsoto suppress a vibration of the coil relative to the magnetic ringassembly 12. This elastic material 29 furthermore serves to damp aforce, which would be generated when the magnetic ring assembly 12 ispress-fitted into the bearing assembly, to thereby prevent the coil frombeing adversely affected by such force.

In the embodiment according to any one of the first to fourth aspects ofthe present invention, the multi-pole magnet assembly 13 is defined by amulti-pole magnet member 16 and an annular core metal 17 as best shownin FIG. 2. The magnet member 16 is in the form of, for example, a rubbermagnet and is secured by vulcanization to the core metal 17. Where thecore metal 17 is employed, the core metal 17 is preferably made of amagnetic material, particularly a ferromagnetic material. The core metal17 may be in the form of either an annular member of a generallyL-shaped section or an annular member of a generally U-shaped section.The annular core metal 17 is fixed in potion as press-fitted on theouter peripheral surface of the inner member 3. The multi-pole magnetassembly 13 may be either a plastic magnet or a sintered magnet and maybe bonded to the outer peripheral surface of the inner member 3 by theuse of, for example, a bonding agent. Where the multi-pole magnetassembly 13 is employed in the form of the plastic magnet or thesintered magnet, the use of the core metal 17 may be dispensed with.

A wireless transmission device 14 is of an annular shape and isintegrated together with, that is, fixedly connected with the magneticring assembly 12. This wireless transmission device 14 is positioned ata location axially outwardly of the magnetic ring assembly 12 and hasits inner and outer diameters generally matching with those of an axialouter end of the magnetic ring assembly 12. The wireless transmissiondevice 14 may be of a box-like configuration instead of the annularconfiguration and may not necessarily be integrated together with themagnetic ring assembly 12, but may be fixedly secured to, for example,the knuckle 10. This wireless transmission device 14 is comprised of atransmitting device containing electronic component parts and an antennaand is electrically powered by the electrical power generator 11. Someor all of the electronic component parts of the wireless transmissiondevice 14 may be accommodated within the magnetic ring assembly 12 ofthe electric power generator 11.

The magnetic ring assembly 12 has its inner peripheral surface of agenerally stepped configuration having a depressed corner area delimitedby the annular side wall 33 and an inner peripheral wall 34 thereof, anda sealing member 18 is mounted in this corner area. This sealing member18 is of a structure including a core metal 19 of a generally L-shapedsection bonded and, hence, integrated together with a sealing element 20made of an elastic material. The sealing element 20 has a plurality ofelastic lips. Although the number of the elastic lips may be suitablychosen, the sealing element 20 so far shown includes a single radial lip21 and two side lips 22.

A slinger 23 made of a stainless steel and defining a seal contact areais provided in the rotatable member 7 so as to confront the sealingmember 18. Specifically, this slinger 23 is press-fitted onto a shoulderof a cup portion 37 of the outer race 15 a of the constant velocityuniversal joint 15 and includes a cylindrical portion 24, slidablyengaged with the radial lip 21 of the sealing member 18, and an inclinedcollar 25 slidably engaged with the side lips 22 and 22 of the sealingmember 18. While the seal contact area with which the radial lip 21 andthe side lips 22 and 22 are slidingly engaged may be defined directly onan outer peripheral surface of the cup portion 37 of the constantvelocity universal joint 15, the use of the slinger 23 is preferred inorder to secure a high rust proof in the seal contact area and also torealize a high performance sealing.

While the core metal 19 referred to above has a hollow cylindrical wall19 a and a radial end wall 19 b extending radially inwardly from one endof the hollow cylindrical wall 19 a, the sealing member 18 having thesealing element 20 covering an outer peripheral surface of the hollowcylindrical wall 19 a of the core metal 19 is mounted to the magneticring assembly 12 with the radial end wall 19 b of the core metal 19 heldin abutment with the annular side wall 33 of the magnetic ring assembly12 and also with the hollow cylindrical wall 19 a of the core metal 19press-fitted into the inner peripheral wall 34 of the magnetic ringassembly 12. A portion 20 a of the sealing element 20 that covers theouter peripheral surface of the hollow cylindrical wall 19 a of the coremetal 19 is formed with an engaging portion 27 over the entirecircumference, or with a plurality of the engaging portions 27 at acorresponding number of locations on the circumference, which engagingportions 27 may be of a recess or projection. On the other hand, theinner peripheral wall 34 of the magnetic ring assembly 12 is formed witha to-be-engaged portion 28 over the entire circumference, or with aplurality of the to-be-engaged portions 28 at a corresponding number oflocations on the circumference, which to-be-engaged portions 28 may beof a recess or projection. Accordingly, when the sealing member 18 ismounted inside the magnetic ring assembly 12, the engaging portions 27of the sealing element 20 are engaged with the to-be-engaged portions 28of the magnetic ring assembly 12, respectively. Although without theengaging portions 27 and the to-be-engaged portions 28 being formed, thesealing member 18 may be fitted inside the inner peripheral wall 34 ofthe magnetic ring assembly 12, formation of the engaging portions 27 andthe to-be-engaged portions 28 is preferred in order to avoid anypossible separation of the sealing member 18 from the magnetic ringassembly 12. It is to be noted that the sealing member 18 may be mountedinside the magnetic ring assembly 12 by fixing the hollow cylindricalwall 19 a of the core metal 19 to the inner peripheral wall 34 of themagnet ring assembly 12 without an outer peripheral surface of thecylindrical wall 19 a of the core metal 19 being covered by the sealingelement 20 or with a part of an free end of the cylindrical wall 19 abeing covered by the sealing member 20 such that the radial end wall 19b of the core metal 19 can be held in abutment with the annular sidewall 33 of the magnetic ring assembly 12.

The outboard sealing member 9 and the inboard sealing member 18cooperate with each other to prevent external saline dirt and grits fromentering the annular working space between the outer and inner members 2and 3. In particular, the inboard sealing member 18 is highly effectivein that three sealing lips including the side lips 22 and 22 and theradial lip 21 provide a high performance seal to avoid ingress of salinedirt and grits from the outside into the annular working space. Sincethe multi-pole magnet assembly 13 of the electric power generator 11 isdisposed inside the high performance seal, there is no possibility thatthe multi-pole magnet assembly 13 may be exposed to foreign matters suchas saline dirt and grits and, therefore, the need to use any additionalsealing elements for a rust proofing and prevention of ingress offoreign matters can advantageously be eliminated.

FIG. 5 illustrates a modified form of the seal contact area according toa second preferred embodiment of the present invention. In thismodification, a core metal 39 of the multi-pole magnet assembly 13 isformed integrally with the slinger 23 that is made of stainless steel.This slinger 23 includes a first hollow cylindrical wall of a reduceddiameter that defines the core metal 39, a second hollow cylindricalwall 41 of a large diameter, an intermediate annular shoulder 40intervening between the first and second hollow cylindrical walls 39 and41, and an inclined collar 42 continued axially outwardly from thesecond hollow cylindrical wall 41 with a free end of the inclined collar42 bent to extend upright in a radially outward direction. This slinger23 is mounted on the inner member 3, particularly the inner race formingmember 3 b with the second hollow cylindrical wall 41 thereofpress-fitted onto a shoulder 43 of the cup portion 37 of the constantvelocity universal joint 15. It is, however, to be noted that instead ofthe second hollow cylindrical wall 41 being press-fitted onto the cupportion 37 of the constant velocity universal joint 15, the slinger 23may be mounted on the inner member 3 by press-fitting the core metal 39onto the inner member 3. Other structural features of the wheel supportbearing assembly shown in FIG. 5 are similar to those shown in anddescribed with reference to FIGS. 1 to 4B in connection with the firstembodiment and, therefore, the details thereof are not reiterated forthe sake of brevity.

FIG. 6 illustrates the wheel support bearing assembly according to athird preferred embodiment of the present invention. This thirdembodiment is featured in that an outer peripheral wall of the magneticring assembly 12 of the electric power generator 11 is provided with acylindrical extension 12 a protruding axially thereof so that theelectric power generator 11 can be mounted on the outer member 2 withthe cylindrical extension 12 a press-fitted onto the outer peripheralsurface of the outer member 2. The cylindrical extension 12 a is anintegral part of a ferromagnetic ring assembly forming a part of themagnetic ring assembly 12. An annular end wall of the electric powergenerator 11 adjacent the outer member 2 is step-less and is held inabutment with an annular end face of the outer member 2. Otherstructural features of the wheel support bearing assembly shown in FIG.6 are similar to those shown in and described with reference to FIGS. 1to 4B in connection with the first embodiment and, therefore, thedetails thereof are not reiterated for the sake of brevity.

FIG. 7 illustrates the wheel support bearing assembly according to afourth preferred embodiment of the present invention. The embodimentshown in FIG. 7 is featured in that the electric power generator 11employed therein is of an axial type in which the multi-pole magnetassembly 13 and the magnetic ring assembly 12 confront with each otherin a direction axially of the wheel support bearing assembly. As such,the core metal 17 is of a generally L-sectioned configuration having ahollow cylindrical wall 44 and a radially outwardly extending annularupright wall 45 lying perpendicular to the hollow cylindrical wall 44,and a magnet member 16 of the multi-pole magnet assembly 13 shown inFIG. 7 is secured to the annular upright wall 45 of the core metal 17.Specifically, the multi-pole magnet assembly 13 has a configuration inwhich the magnet member 16 is held to confront an axially oriented innerside face of the magnetic ring assembly 12 while the hollow cylindricalwall 44 of the core metal 17 is press-fitted onto the outer peripheralsurface of the inner member 3 with the annular upright wall 45 orientedaxially inwardly. Other structural features of the wheel support bearingassembly shown in FIG. 7 are similar to those shown in and describedwith reference to FIGS. 1 to 4B in connection with the first embodimentand, therefore, the details thereof are not reiterated for the sake ofbrevity.

FIGS. 8 to 11 illustrate fifth to eighth preferred embodiments of thepresent invention, respectively. In those embodiments, the wirelesstransmission device 14 is of an annular configuration and is fixedlyconnected with the magnetic ring assembly 12 and is positioned at alocation axially outwardly of the magnetic ring assembly 12 of theelectric power generator 11 with the sealing member 18 arranged radiallyinwardly of such wireless transmission device 14. Those embodimentsshown respectively in FIGS. 8 to 11 differ from each other in asectional shape of the magnet ring assembly 12 and also in respect ofthe manner in which the magnetic ring assembly 12 and the wirelesstransmission device 14 are installed, but other structural featuresthereof than the manner of positioning of the wireless transmissiondevice 14 relative to the magnetic ring assembly 12 are similar andcommon to each other.

To describe the structural features common to all of those embodimentsshown respectively in FIGS. 8 to 11, the magnetic ring assembly 12, eventhough having a slightly different sectional shape for each of thoseembodiments, is of the structure enough to define the claw-pole typeelectric power generator shown in FIG. 4. Also, this magnetic ringassembly 12 includes a pair of ferromagnetic ring members 30 a and 30 b.In addition, the multi-pole magnet assembly 13, the slinger 23 definingthe seal contact area and the sealing member 18 employed in each ofthose embodiments of FIGS. 8 to 11 are similar to those shown in anddescribed with reference to FIGS. 1 to 4B in connection with the firstembodiment of the present invention.

The wireless transmission device 14 includes a wireless transmittingdevice 38 having electronic component parts and an antenna accommodatedtherein, which device 38 is fixed to a mounting ring 26. Some or all ofthe electronic component parts of the wireless transmitting device 38may be built in the magnetic ring assembly 12. The mounting ring 26 hasa generally Z-shaped section delimited by an inner cylindrical body 26 apositioned radially inwardly of the wireless transmitting device 38, anannular stepped wall 26 b lying perpendicular to the inner cylindricalbody 26 a, and an outer cylindrical body 26 c lying perpendicular to theannular stepped wall 26 b and extending axially in a direction counterto the inner cylindrical body 26 a. This mounting ring 26 may be ofone-piece construction including those walls 26 a to 26 c formed by theuse of any known press work. The wireless transmitting device 38 isfixedly mounted externally on the inner cylindrical body 26 a.

The sealing member 18 includes the sealing element 20 which may coverthe outer peripheral surface of the hollow cylindrical wall 19 a of thecore metal 19. This sealing member 18 is accommodated within the innercylindrical body 26 a of the mounting ring 26 with the radial end wall19 b thereof held in abutment with the annular side wall 33 of themagnetic ring assembly 12.

The wireless transmission device 14 has an inner peripheral surfaceformed with a plurality of the to-be-engaged portions 28 which may be inthe form of projections or recesses, while the sealing member 18 isformed with a corresponding number of the engaging portions 27 which maybe in the form of recesses or projections and which engage theassociated to-be-engaged portions 28 on the inner peripheral surface ofthe wireless transmission device 14. Accordingly, the sealing member 18is mounted inside the wireless transmission device 14 with theto-be-engaged portions 28 engaged with the engaging portions 27. Theto-be-engaged portions 28 are formed in the mounting ring 26. Theengaging portions 27 and the to-be-engaged portions 28 may be formedover the entire circumference or at discrete locations.

Hereinafter, each of the fifth to eighth embodiments shown respectivelyin FIGS. 8 to 11 will be described. It is, however, to be noted thatthose embodiments are similar to the first preferred embodimentdescribed with reference to FIGS. 1 to 4B, except for featuresspecifically described hereinbelow.

In the fifth embodiment shown in FIG. 8, the magnetic ring assembly 12has an outer peripheral surface of a generally cylindrical configurationincluding a reduced diameter portion and a large diameter portion withan annular step intervening therebetween. This magnetic ring assembly 12is carried by the outer member 2 with the reduced diameter portionthereof press-fitted into the inner peripheral surface of the outermember 2. In other words, the magnetic ring assembly 12 has an axial endportion press-fitted into the inner periphery of the outer member 2. Theinner peripheral surface and the annular side wall 33 of the magneticring assembly 12 represent a flat surface with no step formed therein.

The mounting ring 26 for the wireless transmission device 14 isintegrated together with the magnetic ring assembly 12 by allowing themounting ring 26 to be firmly sandwiched between the respectiveoutermost peripheral portions 35 and 36 of the first and secondferromagnetic ring members 30 a and 30 b while the annular stepped wall26 b is held in abutment with the annular stepped wall 33 of theferromagnetic ring member 30 b. It is, however, to be noted that, afterthe mounting of the ferromagnetic ring member 30 b and the mounting ring26, a free end of the outermost peripheral portion 35 of theferromagnetic ring member 30 a of the magnetic ring assembly 12 may becrimped to extend close towards the annular stepped wall 26 b of themounting ring 26 to thereby avoid any possible separation of suchmounting members. The inner cylindrical body 26 a protrudes axiallyoutwardly from the annular stepped wall 33 of the magnetic ring assembly12, and the sealing member 18 is engaged in the wireless transmissiondevice 14 with the inner cylindrical body 26 a of the mounting ring 26intervening therebetween. The sealing member 18 is thus engaged in acorner area delimited by the inner cylindrical body 26 a of the mountingring 26 and the annular stepped wall 33 of the magnetic ring assembly12. Material for the mounting ring 26 is, since it is sandwiched withinthe magnetic ring member 12 in the manner described above, chosen to bea magnetic material and, in particular, a magnetic material having arust proof. It is to be noted that the mounting ring 26 may be rigidlyconnected with the magnetic ring assembly 12 by the use of any knownwelding technique.

Since the annular wireless transmission device 14 is positioned axiallyoutwardly of the magnetic ring assembly 12 and is used as an element forcarrying the sealing member 18, any possible use of otherwise requiredprojection for supporting the sealing member of the electric powergenerator 11 can advantageously be eliminated and the length of themagnetic path in the magnetic ring assembly 12 can be reduced to therebylower the magnetic resistance. As a result thereof, the efficiency ofelectric power generation can be increased advantageously and theelectric power generator can be assembled compact in size. Also, in viewof the fact that the annular wireless transmission device 14 is mountedonto and is hence integrated together with the magnetic ring assembly12, the outer and inner members 2 and 3 can be accurately and exactlyaligned coaxially with each other, resulting in increase of the sealingperformance.

In the sixth embodiment shown in FIG. 9, the wireless transmissiondevice 14 is mounted on the outer member 2 by mounting the outercylindrical body 26 c of the mounting ring 26 on the outer peripheralsurface of the outer member 2. In this structure, material for themounting ring 26 does not need to be magnetic provided that it has arust proof. For example, austenite stainless steel such as identified bySUS 304 according to the Japanese Industrial Standard (JIS) may beemployed therefor. However, the magnetic ring assembly 12 may be made ofa material having no rust proof, but having a high magneticpermeability. By way of example, Permalloy®, silicon steel plate, rolledsteel plate or the like may be employed as material for the magneticring assembly 12. The use of the material of a high magneticpermeability is effective to increase the efficiency of electric powergeneration and also to reduce the size of the electric power generator11.

In the seventh embodiment shown in FIG. 10, the magnetic ring assembly12 has a generally rectangular sectional shape and also has itsoutermost peripheral portion 36 protruding axially inwardly, so that themagnetic ring assembly 12 can be capped onto the outer member 2 bypress-fitting the protruding extension to the outer peripheral surfaceof the outer member 2. The wireless transmission device 14 employedtherein is mounted on the magnetic ring assembly 12 with the mountingring 26 mounted under interference fit around the outer periphery of themagnetic ring assembly 12. The outer cylindrical body 26 c of themounting ring 26 extends to a position immediately above the outerperipheral surface of the outer member 2, while the annular stepped wall26 b of the mounting ring 26 is held in contact with the annular steppedwall 33 of the magnetic ring assembly 12. It is, however, to be notedthat the mounting ring 26 may be rigidly connected with the magneticring assembly 12 by the use of any known welding technique.

In the eighth embodiment shown in FIG. 11, the mounting ring 26 isfixedly mounted on the outer member 2 with the outer cylindrical body 26c thereof press-fitted around the outer peripheral surface of the outermember 2. The magnetic ring assembly 12 employed therein has a generallyrectangular sectional shape and is press-fitted into the innerperipheral surface of the outer cylindrical body 26 c of the mountingring 26 to thereby integrate the magnetic ring assembly 12 and thewireless transmission device 14 together.

In describing any one of the foregoing various embodiments of thepresent invention, the electric power generator 11 has been described asconcurrently serving as a rotation detecting device. However, accordingto a broad aspect of the present invention, the use may be made of asensor (not shown), separate from the electric power generator 11, fordetecting the number of revolutions, i.e., the rotational speed, inwhich case the electric power generator 11 may provide an electric powersource for such sensor. By way of example, for the rotational speedsensor, a magnetic sensor such as a Hall element for detecting themulti-pole magnet assembly 13 of the electric power generator 11 may beused, while the multi-pole magnet assembly 13 is concurrently used as arotor of the electric power generator 11 and also as a rotational speeddetecting member. Where a rotational speed detecting sensor separatefrom the electric power generator 11 is employed, the wirelesstransmission device 14 may be used to transmit wireless a detectionsignal outputted from the sensor. In such case, the electric powergenerated by the electric power generator 11 is also used for drivingthe wireless transmission device 14. Also, where a sensor for detectinga parameter (such as vibrations or temperature) other than therotational speed is employed being separate from the electric powergenerator 11, the wireless transmission device 14 may be used totransmit wireless the rotational speed detection signal detected andoutputted by the electric power generator 11 and such parameter signaldetected and outputted by the parameter detecting sensor.

In the embodiment according to a fifth aspect of the present invention,as shown in FIG. 12, a coil 65 wound around a coil bobbin 64 isaccommodated within the magnetic ring assembly 12 which defines a yokeof the electric power generator 11. The coil bobbin 64 is in the form ofa generally U-sectioned ring member having opposite end walls 64 a and64 b and a bottom wall 64 c connecting the opposite end walls 64 a and64 b together to define a groove that opens radially outwardly. The coil65 is wound and, hence, accommodated within the groove delimited by thewalls 64 a to 64 c. It is to be noted that the bottom wall 64 c of thecoil bobbin 64 extends axially outwardly from the end wall 64 b todefine a cylindrical extension 64 ca, and an electric circuit 66 thatutilizes an output from the electric power generator 11 is disposedwithin an annular space delimited between the end wall 64 b and thecylindrical extension 64 ca. The coil bobbin 64 for the coil 65 is fixedon the magnetic ring assembly 12 by means of an elastic layer 63 (SeeFIG. 14) prepared from an elastic bonding material, which elastic layer63 fills up axial and radial gaps 68 and 69 delimited between the coilbobbin 64 and the magnetic ring assembly 12. The elastic layer 63 may bea molded resin having an elasticity. Thus, since the coil bobbin 64 iselastically fixed to the magnetic ring assembly 12 through the elasticlayer 63, not only can an undesirable deformation of the magnetic ringassembly 12 be prevented, but an undesirable direct transmission ofvibrations to the coil 65 can also be avoided.

The electric circuit 66 includes an electric circuit substrate 67 havingvarious electric component parts mounted thereon, which electric circuitsubstrate 67 is fitted to the end wall 64 b of the coil bobbin 64. FIG.13 illustrates a positional connection between the ferromagnetic ringmember 30 a, which forms a part of the magnetic ring assembly 12, andthe coil bobbin 64 that is fitted to the ferromagnetic ring member 30 a,and FIG. 14 illustrate that connection on an enlarged scale. As bestshown in FIG. 14, the coil 65 has a lead line 65 a connected directly toan input terminal 91 of the electric circuit substrate 67, therebyeliminating a terminal treatment such as connecting the lead line of thecoil with an extra bold electric line such as required in theconventional wheel support bearing assembly. The electric circuitsubstrate 67 referred to above is preferably of either a generallyarcuate shape such as shown in FIG. 15A or an annular shape such asshown in FIG. 15B so that the electric circuit substrate 67 when fittedto the end wall 64 b of the coil bobbin 64 can follow the curvature ofthe end wall 64 b. Accordingly, the electric circuit 66 can be compactlyprovided in the coil bobbin 64 without allowing any portion of theelectric circuit 66 to protrude outwardly from the contour of the coilbobbin 64.

The electric circuit 66 includes, as shown in a circuit block diagram ofFIG. 16, a signal processing circuit 240 for processing an electricpower output generated by the electric power generator 11 to provide arotational speed detection signal indicative of the rotational speed, atransmitter circuit 242 for converting the rotational speed detectionsignal, processed by the signal processing circuit 240, into a radiowave which is subsequently transmitted wireless from a transmittingantenna 244 connected with such transmitter circuit 242, and an electricpower source circuit 243 for providing an electric power source forsupplying the signal processing circuit 240 and the transmitter circuit242 with the electric power output generated by the electric powergenerator 11. The transmitter circuit 242 is comprised of an oscillatingand modulating circuit. The transmitter circuit 242 and the transmittingantenna 244 altogether constitutes a transmitting unit 241A of awireless transmission device 241. The wireless transmission device 241is made up of the transmitting unit 241A and a receiving unit 241B. Thereceiving unit 241B includes a receiving antenna 252, and a receivercircuit 253 comprised of a tuning and demodulating circuit for tuningthe wireless transmitted signal received for demodulation. It is to benoted that for detection of the rotational speed of the wheel, aseparate sensor dedicated therefor may be employed instead of theelectric power output from the electric power generator 11 being usedtherefor such as in the embodiment now under discussion. The rotationalspeed detection signal received by the receiving unit 241B may beutilized for control of an anti-skid braking system, or the like.

The transmitting antenna 244 of the transmitting unit 241A is, as bestshown in FIG. 12, disposed on an outer periphery of a reduced diameterportion 30 ca of the ferromagnetic ring member 30 c forming a part ofthe magnetic ring assembly 12, together with an extra member 54. Thetransmitting antenna 244 and the transmitter circuit 242 in the electriccircuit 66 are electrically connected with each other by means of wiring(not shown) passing through a small insertion hole defined in theannular side wall 33 of the magnetic ring assembly 12. This smallinsertion hole defined in the annular side wall 33 of the magnetic ringassembly 12 for the passage of the wiring is treated to have a waterproofing property when the extra member 54 provided together with thetransmitting antenna 244 is fitted and, accordingly, any undesirableingress of foreign matter such as saline dirt and grits through thesmall insertion hole into the magnetic ring assembly 12 can beeffectively avoided.

FIG. 17 illustrates one example of the electric power source circuit 243referred to above. As shown therein, an electric current generated bythe electric power generator 11 is rectified and then smoothed by arectifier circuit 247 and a smoothing capacitor 248, respectively, andis subsequently outputted from an electric power output terminal VCCthrough a diode 249. A super capacitor 250 is disposed in a stagefollowing the diode 249 and between the electric power output terminalVCC on a plus side and a ground terminal GND, and a parallel circuit 251including a diode and a resistor is interposed between a plus end of thesuper capacitor 250 and the electric power output terminal VCC.

As best shown in FIG. 12, the multi-pole magnet assembly 13 includes themulti-pole magnet member 16 and the annular core metal 17. The magnetmember 16 is in the form of, for example, a rubber magnet and is securedby vulcanization to the core metal 17. Where the core metal 17 isemployed, the core metal 17 is preferably made of a magnetic material,particularly a ferromagnetic material. The core metal 17 may be in theform of either an annular member of a generally L-shaped section or anannular member of a generally U-shaped section. The annular core metal17 is fixed in potion as press-fitted on the outer peripheral surface ofthe inner member 3. The multi-pole magnet assembly 13 may be either aplastic magnet or a sintered magnet and may be bonded to the outerperipheral surface of the inner member 3 by the use of, for example, abonding agent. Where the multi-pole magnet assembly 13 is employed inthe form of the plastic magnet or the sintered magnet, the use of thecore metal 17 may be dispensed with.

The sealing member 18 is disposed at a location radially inwardly of thereduced diameter portion 30 ca of the ferromagnetic ring member 30 cforming a part of the magnetic ring assembly 12. This sealing member 18includes the sealing element 20 of an elastic material integrated bybonding together with the core metal 19. The core metal 19 is of agenerally L-shaped section. The sealing element 20 has a plurality ofelastic lips. Although the number of the elastic lips may be suitablychosen, the sealing element 20 so far shown includes a single radial lip21 and two side lips 22. The slinger 23 made of a stainless steel anddefining a seal contact area is disposed on the rotatable member 7 inface-to-face relation with the sealing member 18.

The operation of the electric power generator 11 of the structurediscussed above with reference to FIGS. 12 to 17 will now be described.The electric power output from the electric power generator 11 isinputted to the electric circuit 66 disposed inside the magnetic ringassembly 12 that defines the yoke of the electric power generator 11 andis then processed by the signal processing circuit 240 to provide therotational speed detection signal. The electric power output from theelectric power generator 11 is also supplied to the electric powersource circuit 243 and then provides the signal processing circuit 240and the transmitter circuit 242 with an electric power after having beenrectified and smoothed by the rectifier circuit 247 and the smoothingcapacitor 248, respectively. The resultant rotational speed detectionsignal is thereafter transmitted wireless in the form of a radio wavefrom the transmitter circuit 242 to the receiving unit 241B through thetransmitting antenna 244.

Since the electric power source circuit 243 incorporates the supercapacitor 250 as a charging circuit, the electric power generated by theelectric power generator 11 can be charged in the super capacitor 250during a high speed rotation of the rotatable member 7 and, in the eventthat the rotatable member 7 then driven at a high speed slows down to aspeed low enough to cause the electric power generator 11 to generate aninsufficient amount of electric power, the electric power charged in thesuper capacitor 250 can be utilized to compensate for reduction inelectric power during a low speed rotation of the rotatable member 7, tokeep the various electronic components sufficiently poweredelectrically. FIG. 18A illustrates the charging during the high speedrotation of the rotatable member 7 whereas FIG. 18B illustrates thedischarging during the low speed rotation of the rotatable member 7.Specifically, during the high speed rotation, the electric powergenerated by the electric power generator 11 is rectified and smoothedby the rectifier circuit 247 and the smoothing capacitor 248,respectively, into a direct current voltage which is utilized as anelectric power source for the various electric components and is in partcharged in the super capacitor 250 through the resistor of the parallelcircuit 251 as shown in FIG. 18A. On the other hand, during the lowspeed rotation, the electric power is supplied from the super capacitor250 through the diode of the parallel circuit 251 as shown in FIG. 18B.Thus, the rotational speed detection signal can be assuredly transmittedeven during the low speed rotation of the rotatable member 7 at whichthe electric power generated by the electric power generator 11 isinsufficient.

In particular, in this embodiment now under discussion, since theelectric circuit 66 that utilizes the output of the electric powergenerator 11 is disposed inside the magnetic ring assembly 12, shown inFIG. 14, which defines the yoke of the electric power generator 11,electrical connection of the coil 65 of the electric power generator 11with the electric circuit 66 can easily be accomplished and, therefore,the need to use a special measure to prevent a possible breakage of thewiring used therefor and, also, a protective casing for protecting theelectric circuit 66 from external environments can advantageously bedispensed with, allowing the structure to be assembled compact in sizeand easily. Also, since the electric circuit substrate 67 carrying theelectric circuit 66 thereon is mounted on the coil bobbin 64 of theelectric power generator 11, electrical connection between the coil 65of the electric power generator 11 and the electric circuit 66 canadvantageously be achieved by a simplified procedure.

Moreover, since the electric power generator 11 is of a structureincluding the multi-pole magnet assembly 13 having a plurality ofalternating magnetic poles arranged in a circumferential direction asshown in FIG. 12, and the magnetic ring assembly 12 accommodatingtherein the coil 65, the multi-polarization makes it possible for therotational speed to be accurately detected and for the electric powergenerator 11 to generate the electric power efficiently with asimplified and compact structure. Considering that the magnetic ringassembly 12 is of the claw-pole type having the plural claws 31 a and 31b interleaved with each other to define the alternating magnetic polesas shown in FIG. 4A, the use thereof in combination with the multi-polemagnet assembly 13 makes it possible for the rotational speed to befurther accurately detected.

In addition, since the use is made of the wireless transmission device241 for transmitting wireless the rotational speed detection signaloutputted from the electric power generator 11 or the output from therotational speed sensor utilizing the electric power generator 11 as itselectric power source and since the electric circuit 66 disposed insidethe magnetic ring assembly 12 that defines the yoke of the electricpower generator 11 includes the rectifier circuit 247 for rectifying thegenerated electric power, the signal processing circuit 240 and thetransmitting circuit 242 of the wireless transmission device 241, noextra electric power source dedicated for the wireless transmission isneeded and the rotational speed detection signal can be transmitted tothe outside of the wheel support bearing assembly with no risk ofbrakeage of any wiring.

FIGS. 19 to 25 illustrate different manners in which the electriccircuit 66 is secured to the coil bobbin 64, respectively. Any of thosemodifications shown in FIGS. 19 to 25 can be equally applied to theembodiment shown in and described with reference to FIG. 12.

In the example shown in FIG. 19, the cylindrical extension 64 ca of thecoil bobbin 64 has its outer periphery formed with projections 55 forsecurement of the electric circuit substrate 67. The presence of theprojections 55 is effective to axially fix the electric circuitsubstrate 67 disposed to follow the curvature of the end wall 64 b ofthe coil bobbin 64.

In the example shown in FIG. 20, an outer peripheral edge portion of theend wall 64 b of the coil bobbin 64 is formed with a plurality ofengagement pawls 56 for securement of the electric circuit substrate 67.The electric circuit substrate 67 fitted to the end wall 64 b of thecoil bobbin 64 can be axially fixed in position by those engagementpawls 56. Each of those engagement pawls 56 extends axially from theouter peripheral edge portion of the end wall 64 b a distance aboutequal to the thickness of the electric circuit substrate 67, with itstip bent to protrude radially inwardly to thereby secure the electriccircuit substrate 67 against the end wall 64 b of the coil bobbin 64.

In the example shown in FIGS. 21A and 21B, the electric circuitsubstrate 67 has its inner peripheral edge portion formed with one ormore positioning cutouts 57 and, on the other hand, the end wall 64 b ofthe coil bobbin 64 has its base formed with corresponding retainerprojections 58 engageable in the positioning cutouts 57. By causing theretainer projections 58 to engage in the corresponding cutouts 57, theelectric circuit substrate 67 can be fixed in position with nopossibility of being displaced in a direction circumferentially thereof.

In the example shown in FIGS. 22A and 22B, the electric circuitsubstrate 67 is formed with one or more engagement holes 59 forsecurement and, on the other hand, the end wall 64 b of the coil bobbin64 is formed with corresponding positioning projections 60 engageable inthe engagement holes 59. By engaging the positioning projections 60 inthe corresponding engagement holes 59, it will readily be seen that theelectric circuit substrate 67 can be not only fixed in position in adirection circumferentially thereof but also secured without beingdisplaced in a direction axially thereof.

In the example shown in FIG. 23, one of the opposite end walls of thecoil bobbin 64, that is, the end wall 64 b thereof shown in FIG. 12 isdispensed with and, instead thereof, the annular electric circuitsubstrate 67 is used as a substitute for the end wall 64 b. In otherwords, the electric circuit substrate 67 forms a part of the coil bobbin64. In such case, the electric circuit substrate 67 is fixed in positionon the coil bobbin 64 against an end face of the coil 65 by means of aplurality of projections 61 formed on the outer periphery of thecylindrical extension 64 ca of the coil bobbin 64. The use of theelectric circuit substrate 67 as a substitute for the end wall 64 b ofthe coil bobbin 64 is effective to reduce the axial dimension of theentire electric power generator 11.

In the example shown in FIG. 24, a circuit pattern of the electriccircuit 66 is formed directly on the end wall 64 b of the coil bobbin64, followed by mounting of the various electric component parts on thecircuit pattern so formed on the end wall 64 b to thereby complete theelectric circuit 66. In other words, in this example, the end wall 64 bof the coil bobbin 64 is used as the electric circuit substrate 67 and,accordingly, the axial dimension of the entire electric power generator11 can advantageously be reduced.

In the example shown in FIG. 25, the embodiment shown in and describedwith reference to FIG. 12 is modified in such a manner that at the timeof assembling the magnetic ring assembly 12 with the three ferromagneticring members 30 a, 30 b and 30 c, a plurality of spacers 62 made of anelastic material are circumferentially disposed between the electriccircuit substrate 67 and the annular side wall 33 of the magnetic ringassembly 12 to thereby assist fixing of the electric circuit substrate67 in a direction axially thereof. In this case, respective portions ofa surface of the electric circuit substrate 67 with which thecorresponding spacers 62 contact are defined as blank areas where noelectric component parts are mounted.

In describing any of the foregoing embodiments of the present invention,reference has been made to the electric circuit 66 in its entiretydisposed inside the magnetic ring assembly 12 that defines the yoke ofthe electric power generator 11. However, a high frequency circuitsection of the electric circuit 66 which requires adjustment may bedisposed outside the magnetic ring assembly 12 together with thetransmitting antenna 244 and the external member 54. By way of example,the high frequency circuit section and the transmitting antenna 244 maybe disposed on an outer periphery of the reduced diameter portion 30 caof the ferromagnetic ring member 30 c forming a part of the magneticring assembly 12. The electric power source circuit 243 and the signalprocessing circuit 240, both of which do not require any adjustment, areto be disposed inside the magnetic ring assembly 12. By so constructing,as an electric power generator unit having the electric power sourcecircuit built therein, the assembly can be used in various applications,but not limited to the wireless transmission use.

In the embodiment according to a sixth aspect of the present invention,as shown in FIG. 2, the magnetic ring assembly 12 is in the form of atubular ring having a substantially closed hollow defined therein. Theouter peripheral surface of the magnetic ring assembly 12 represents agenerally stepped cylindrical surface having the stepped portion orshoulder 40 defined at one end thereof. The stepped portion 40 is madeup of a generally U-shaped corner defined by a peripheral surfaceportion 40 a and a side surface portion 40 b. The peripheral portion 40a has a diameter reduced relative to a large diameter portion thatdefines the outer peripheral surface of the magnetic ring assembly 12.The magnetic ring assembly 12 is directly press-fitted at the peripheralsurface portion 40 a into the inner peripheral surface of the outermember 2 adjacent one end thereof. This press-fit is carried out untilthe side surface portion 40 b of the stepped portion 40 is brought intoabutment with the end face of the outer member 2 to thereby position themagnetic ring assembly 12 with respect to the axial direction. Themagnetic ring assembly 12 has a seal mount 41 of a generally U-shapedconfiguration defining a stepped form, which seal mount 41 is defined inan inner peripheral surface of the magnetic ring assembly 12 axiallyopposite to the stepped portion 40. The sealing member 18 is thusmounted on the seal mount 41.

Referring to FIG. 2, the multi-pole magnet assembly 13 is in the form ofa ring member magnetized to have a plurality of alternating magneticpoles spaced an equal distance from each other in a directioncircumferentially thereof. This multi-pole magnet assembly 13 is made upof the multi-pole magnet member 16 and the annular core metal 17. Themagnet member 16 is in the form of, for example, a rubber magnet and issecured by vulcanization to the core metal 17. Where the core metal 17is employed, the core metal 17 is preferably made of a magneticmaterial, particularly a ferromagnetic material. The core metal 17 maybe in the form of either an annular member of a generally L-shapedsection or an annular member of a generally U-shaped section. Theannular core metal 17 is fixed in potion as press-fitted on the outerperipheral surface of the inner member 3. The multi-pole magnet assembly13 may be either a plastic magnet or a sintered magnet and may be bondedto the outer peripheral surface of the inner member 3 by the use of, forexample, a bonding agent. Where the multi-pole magnet assembly 13 isemployed in the form of the plastic magnet or the sintered magnet, theuse of the core metal 17 may be dispensed with.

The wireless transmission device 14 serves as a device for transmittingwireless the electric power generated by the electric power generator 11as the rotational speed detection signal, i.e., the signal indicative ofthe number of revolutions of the wheel. This wireless transmissiondevice 14 so far shown is of an annular shape and is fixedly connectedwith the magnetic ring assembly 12. This wireless transmission device 14is positioned at a location axially outwardly of the magnetic ringassembly 12 and has its inner and outer diameters generally matchingwith those of an axial outer end of the magnetic ring assembly 12. Thewireless transmission device 14 may be of a box-like configurationinstead of the annular configuration and may not necessarily beconnected with the magnetic ring assembly 12, but may be fixedly securedto, for example, the outer member 2 or the knuckle 10. Some or all ofthe electronic component parts of the wireless transmission device 14may be included within the magnetic ring assembly 12 of the electricpower generator 11.

The wireless transmission device 14 referred to above is basicallysimilar to that shown in the circuit block diagram of FIG. 16 and, whilethe details thereof are not reiterated for the sake of brevity, as shownin FIG. 16, the sensor 254, separate from the electric power generator11, for detecting the rotational speed or any other parameter such asvibrations or temperature may be disposed in or in the vicinity of thebearing assembly so that the signal outputted from the separate sensor254 can be transmitted wireless by the wireless transmitting means 241.In such case, the electric power generated by the electric powergenerator 11 is utilized to electrically drive both of the separatesensor 254 and the wireless transmitting means 241.

The seal mount 41 defined in the magnetic ring assembly 12 is, as shownin FIG. 2, in the form of a stepped member defining a generally U-shapedcorner area delimited by the side wall 33 and the inner peripheral wall34. The sealing member 18 is mounted on the seal mount 41 of the steppedconfiguration. This sealing member 18 is of a structure including a coremetal 19 of a generally L-shaped section integrated together with thesealing element 20 made of an elastic material. The sealing element 20has one or more elastic lips. Although the number of the elastic lipsforming the sealing element 20 may be suitably chosen, the sealingelement 20 so far shown includes a single radial lip 21 and two sidelips 22. Thus, since the magnetic ring assembly 12 is provided with theseal mount 41 and the sealing member 18 is in turn mounted on the sealmount 41, the sealing member 18 can easily be mounted.

The slinger 23 made of a stainless steel and defining a seal contactarea is provided in the rotatable member 7 so as to confront the sealingmember 18. Specifically, this slinger 23 is press-fitted onto a shoulderof the cup portion 37 of the outer race 15 a of the constant velocityuniversal joint 15 and includes the cylindrical portion 24, relativelyslidably engaged with the radial lip 21 of the sealing member 18, andthe inclined collar 25 relatively slidably engaged with the side lips 22and 22 of the sealing member 21.

The sealing member 18 having the sealing element 20 covering an outerperipheral surface of the hollow cylindrical wall 19 a of the core metal19 is mounted to the magnetic ring assembly 12 with the radial end wall19 b of the core metal 19 held in abutment with the annular side wall 33of the magnetic ring assembly 12 and also with the hollow cylindricalwall 19 a of the core metal 19 press-fitted into the inner peripheralwall 34 of the magnetic ring assembly 12. The portion 20 a of thesealing element 20 covering the outer peripheral surface of the hollowcylindrical wall 19 a of the core metal 19 is formed with the engagingportion 27 over the entire circumference, or with a plurality of theengaging portions 27 at a corresponding number of locations on thecircumference, which engaging portions 27 may be of a recess orprojection. On the other hand, the inner peripheral wall 34 of themagnetic ring assembly 12 is formed with the to-be-engaged portion 28over the entire circumference, or with a plurality of the to-be-engagedportions at a corresponding number of locations on the circumference,which to-be-engaged portions 28 may be of a recess or projection.Accordingly, when the sealing member 18 is mounted inside the magneticring assembly 12, the engaging portions 27 of the sealing element 20 areengaged with the to-be-engaged portions 28 of the magnetic ring assembly12, respectively. Accordingly, the outboard sealing member 9 and theinboard sealing member 18 cooperate with each other to prevent externalsaline dirt and grits from entering the annular working space betweenthe outer and inner members 2 and 3.

The operation of the foregoing structure will now be described. When theinner member 3 carrying the multi-pole magnet assembly 13 of theelectric power generator 11 rotates together with the wheel, change influx interlinkage resulting from the rotation results in an electricpower that is outputted by the magnetic ring assembly 12 carried by theouter member 2 confronting with the inner member 3. The electric poweroutput so generated from the electric power generator 11 is supplied tothe wireless transmission device 241 which subsequently transmitswireless a radio wave descriptive of the rotational speed of the wheel.Specifically, the electric power output so generated is processed by thesignal processing circuit 240 to provide the rotational speed detectionsignal of the wheel which is in turn transmitted from the transmittercircuit 242 to the receiving unit 253 through the transmitting antenna244.

In this rolling bearing assembly equipped with this electric powergenerator 11, the magnetic ring assembly 12 of the electric powergenerator 11 is directly press-fitted into the inner periphery of theouter member 2 through the peripheral surface portion 40 a of thestepped portion 40 and, accordingly, the electric power generator 11 canbe easily and accurately incorporated in the bearing assembly with aminimized number of component parts. In other words, the number ofcomponent parts can advantageously be reduced since no extra mountingmember such as required in the conventional bearing assembly of asimilar kind to mount the magnetic ring assembly 12 on the outer member2 does not intervene therebetween. Also, since the magnetic ringassembly 12 is press-fitted directly into the inner periphery of theouter member 2 having a machining precision, the magnetic ring assembly12 can be highly accurately positioned enough to secure a gap betweenthe magnetic ring assembly 12 and the multi-pole magnet assembly 13. Inaddition, since the side surface portion 40 b of the stepped portion 40of the magnetic ring assembly 12 is engaged with the annular end face ofthe outer member 2, the magnetic ring assembly 12 can be axiallypositioned and positioning accuracy of the electric power generator 11can accordingly be increased. Yet, since the positioning accuracy of themagnetic ring assembly 12 in the axial direction can advantageously besecured, the axial position of the sealing member 18 that is fitted tothe magnetic ring assembly 12 can be precisely controlled to therebyfacilitate management of the sealing performance.

The magnetic ring assembly 12 is made up of two divided ferromagneticring members 30 a and 30 b held axially in face-to-face relation witheach other with their outermost peripheral portions 35 and 36 cappedrelative to each other, while the outermost peripheral portion 35 of theferromagnetic ring member 30 a having the stepped portion 40 formedthereon is positioned radially externally of the outermost peripheralportion 36. Accordingly, the strength with which the respectiveoutermost peripheral portions 35 and 36 of the ferromagnetic ringmembers 30 a and 30 b are engaged with each other can be increased asthe magnetic ring assembly 12 undergoes deformation upon mountingthereof on the outer member 2. For this reason, an undesirable increasein magnetic resistance of the magnetic circuit defined by the magneticring assembly 12, which would occur in the area of contact between theferromagnetic ring members 30 a and 30 b forming the magnetic ringassembly 12, can advantageously be avoided to thereby secure theelectric power generated by the electric power generator 11.

Also, in the illustrated embodiment, the magnetic ring assembly 12, thewireless transmission device 14 and the sealing member 18 can bearranged in a minimized space. Specifically, since the magnetic ringassembly 12 is mounted on the outer member 2, the sealing member 18 isfitted to the inner periphery opposite to the area on which the magneticring assembly 12 is mounted, and the ring-shaped wireless transmissiondevice 14 is disposed axially in side-by-side fashion with the magneticring assembly 12, the magnetic ring assembly 12, the wirelesstransmission device 14 and the sealing member 18 can efficiently bearranged in a generally triangular-sectioned, relatively narrow spaceencompassed between the outer race 15 a of the constant velocityuniversal joint 15, mounted on the inner member 3, and the knuckle 10.

It is to be noted that in the foregoing embodiment, instead of theseparate use of the core metal 17 of the multi-pole magnet assembly 13and the slinger 23, the core metal 17 and the slinger 23 may beintegrally formed in one-piece construction.

In a different preferred embodiment of the present invention, theembodiment shown in and described with reference to FIGS. 1 and 2 may bemodified in such a manner that instead of the seal mount 41 provided inthe magnetic ring assembly 12, the mounting ring 26 defining a sealmount for the support of the sealing member 18 is formed in a portionaxially opposite to the stepped portion 40 of the magnetic ring assembly12 as shown in FIG. 8. The mounting ring 26 is a stepped cylindricalmember of a generally Z-shaped section delimited by the innercylindrical body 26 a, the annular stepped wall 26 b and the outercylindrical body 26 c defined in the order from the inboard side towardsthe outboard side in an axial direction. This mounting ring 26 ismounted on the magnetic ring assembly 12 with the outer cylindrical body26 c thereof clamped between the respective outermost peripheralportions 35 and 36 of the ferromagnetic ring members 30 a and 30 bforming respective parts of the magnetic ring assembly 12. While anouter end wall of the magnetic ring assembly 12 is flat, the innercylindrical body 26 a of the mounting ring 26 protrudes axiallyoutwardly from a portion intermediate between inner and outer diametersof the flat annular end face of the magnetic ring assembly 12. Thesealing member 18 is fitted inside the inner cylindrical body 26 a ofthe mounting ring 26. The inner cylindrical body 26 a of the mountingring 26 is formed with the to-be-engaged portion 28 over the entirecircumference thereof or with a plurality of the to-be-engaged portionsat a corresponding number of locations on the circumference thereof,which to-be-engaged portions 28 may be, for example, lancedprotuberances. The wireless transmission device 14 having an annularshape conforming to the curvature of the inner cylindrical body 26 a ismounted on an outer periphery of the inner cylindrical body 26 a of themounting ring 26. The mounting ring 26 is made of a magnetic material sothat it can cooperate with the magnetic ring assembly 12 to define ayoke of the electric power generator 11. Other structural features thanthose described hereinabove are similar to those described in connectionwith the previously described embodiments and, therefore, the detailsthereof are not reiterated for the sake of brevity.

According to the foregoing embodiment, since the mounting ring 26 isprovided in the magnetic ring assembly 12 and the sealing member 18 isfitted to the inner periphery thereof, even this embodiment is effectiveto permit the sealing member 18 to be easily mounted. Although as anextra component part the mounting ring 26 is required, the magnetic ringassembly 12 can have a simple shape because no stepped portion or thelike that defines the seal mount such as indicated by 41 in FIG. 2 neednot be formed in the magnetic ring assembly 12. Also, if the mountingring 26 is fitted to the magnetic ring assembly 12 beforehand, themounting ring 26 and the magnetic ring assembly 12 can be treated as asingle integer at the time of assemblage of the magnetic ring assembly12. In addition, since the sealing member 18 is disposed radiallyinwardly of the inner cylindrical body 26 a of the mounting ring 26while the wireless transmission device 14 is disposed radially outwardlyof the inner cylindrical body 26 a of the mounting ring 26, the axialdimension can advantageously be minimized.

In a further preferred embodiment of the present invention, the mountingring 26 employed in the embodiment shown in and described with referenceto FIG. 8 is modified as follows. Specifically, the mounting ring 26shown in FIG. 9 is mounted on the outer member 2 with its outercylindrical body 26 c press-fitted onto the outer peripheral surface ofthe outer member 2. The magnetic ring assembly 12 mounted on the outermember 2 has its outer peripheral surface and a portion of an outerannular end face covered by the outer cylindrical body 26 c and thestepped wall 26 b of the mounting ring 26. As is the case with theembodiment shown in and described with reference to FIG. 8, the sealingmember 18 is fitted inside the inner cylindrical body 26 a of themounting ring 26 with the wireless transmission device 14 mountedexternally on such inner cylindrical body 26 a. Also, the engagingportions 27 and the to-be-engaged portions 28 are also provided. Otherstructural features than those described above are similar to thoseshown in and described with reference to FIG. 8 in connection with theprevious embodiment.

In the embodiment shown in FIG. 9, since the magnetic ring assembly 12is covered by the mounting ring 26 and the sealing member 18, there isno possibility that the magnetic ring assembly 12 may be exposed toforeign matter such as saline dirt and grits and, therefore, no rustproofing is needed in the magnetic ring assembly 12. For this reason, amaterial having a higher magnetic permeability than that of a magneticstainless material, such as an ordinary rolled steel plate, siliconsteel plate or Permalloy®, can advantageously be employed as materialfor the magnetic ring assembly 12. Thus, considering that the magneticring assembly 12 can be made of the material having a high magneticpermeability, the resultant electric power generator 11 can have anincreased capability of generating the electric power and the electricpower generator 11 can have a size advantageously reduced for the sameelectric power output. Also, the provision of the mounting ring 26 ofthe generally Z-shaped configuration is effective to avoid any possibleseparation of the electric power generator 11 from the bearing assemblywhich would otherwise occur under the influence of vibrations.

In a still further preferred embodiment, the embodiment shown in anddescribed with reference to FIG. 2 is modified to render the electricpower generator 11 to be of an axial type in which the multi-pole magnetassembly 13 and the magnetic ring assembly 12 confront with each otherin a direction axially of the wheel support bearing assembly. The coremetal 17 employed therein is of a generally L-sectioned configurationhaving the hollow cylindrical wall 44 and the radially outwardlyextending annular upright wall 45 lying perpendicular to the hollowcylindrical wall 44, and the multi-pole magnet assembly 13 employedtherein includes a magnet member 16 fixedly mounted on the annularupright wall 45 of the core metal 17. The magnetic ring assembly 12 isprovided with a comb-shaped arrangement of the claws 49 a and 49 bdisposed in a plane confronting the multi-pole magnet assembly 13. Otherstructural features than those described above are similar to thoseemployed in the previously described embodiment and, therefore, thedetails thereof are not reiterated for the sake of brevity.

It is to be noted that although in any one of the above describedvarious embodiments of the present invention, the magnetic ring assembly12 has been described and shown as mounted on the outer member 2, thepresent invention can be equally applied to the structure in which themagnetic ring assembly 12 is fixedly mounted on the inner member 7. Insuch case, the stepped portion 40 of the magnetic ring assembly 12 hasto be disposed radially inwardly thereof.

Hereinafter, a preferred embodiment of the present invention accordingto a seventh aspect thereof will be described in detail with particularreference to FIGS. 26 to 28. This embodiment is directed to the wheelsupport bearing assembly equipped with the electric power generatorserving as a rotation sensor, The illustrated wheel support bearingassembly includes a stationary member 101 made up of an outer member 102and a knuckle 110. The outer member 102 is secured through a flange 102a to the knuckle 110 which is in turn fixed to an automobile bodystructure or chassis. The wheel support bearing assembly also includes arotatable member 107 comprised of an inner member 103 and an outer race115 a of a constant velocity universal joint 115 secured to an innerperipheral surface of the inner member 103. The constant velocityuniversal joint 115 includes a shank 116 extending integrally from theouter race 115 a and having a large diameter portion 116 a adjacent theouter race 115 a and a reduced diameter portion 116 b remote from theouter race 115 a. This constant velocity universal joint 115 isconnected with the inner member 103 for rotation together therewith bymeans of a splined engagement achieved between an outer peripheralsurface of the reduced diameter portion 116 b and the inner peripheralsurface of the inner member 103. The constant velocity universal joint115 has its outer race 15 a firmly clamped with the inner member 103 bymeans of an anchor nut 117 fastened to an outboard end of the reduceddiameter portion 116 b.

The outer member 102 has its inner peripheral surface formed with aplurality of, for example, two, axially spaced outer raceways 105 a and105 b and, correspondingly, the inner member 103 has its outerperipheral surface formed with axially spaced inner raceways 106 a and106 b aligned respectively with the raceways 105 a and 105 b. The innermember 103 includes a hub wheel 103A and an inner race forming member103B, and the inner raceways 106 a and 106 b referred to above aredefined in the hub wheel 103A and the inner race forming member 103B,respectively. Circumferentially extending rows of rolling elements 104are accommodated within an annular working space defined between theouter and inner members 102 and 103 and are received in part within theouter raceways 105 a and 105 b and in part within the inner raceways 106a and 106 b, respectively. The rolling elements 104 of eachcircumferential row are retained in position by a retainer or cage 108.The inner member 103 has a wheel mounting flange 103 a formed therewithand a wheel is secured to the wheel mounting flange 103 a by means of aplurality of bolts 114. The outer member 102, the inner member 103, therows of the rolling elements 104 and the respective retainers 108altogether constitute a rolling bearing assembly with the outer andinner members 102 and 103 serving as raceways of the rolling bearingassembly. An outboard open end of the annular working space between theouter and inner members 102 and 103 that is adjacent the wheel mountingflange 103 a is sealed by an outboard sealing member 109. An electricpower generator 111 is disposed in an inboard open end of the rollingbearing assembly.

The electric power generator 111 includes a multi-pole magnet assembly112 having a plurality of alternating magnetic poles N and S arranged ina circumferential direction thereof and a magnetic ring assembly 113confronting the multi-pole magnet assembly 112. An end face of the outermember 102 on an inboard side is axially inwardly set back from a planeflush with an end face of the inner member 103, leaving a space in whichthe magnetic ring assembly 113 of the electric power generator 111 isarranged. The magnetic ring assembly 113 is fitted inside an innerperiphery of an outer member mount 110 a of the knuckle 110 whereas themulti-pole magnet assembly 112 is fitted externally around the innermember 103. The magnetic ring assembly 113 is provided with a wirelesstransmission device 120 for transmitting wireless the electric poweroutput of the electric power generator 111 as a rotational speeddetection signal indicative of the number of revolutions of a wheel.

The magnetic ring assembly 113 is mounted on the knuckle 110 through asupport plate 118 as shown in FIG. 28. This support plate 118 includes acylindrical portion 118 a following an inner periphery of the outermember mount 110 a representing a ring shape in the knuckle 110 and aradially outwardly extending mounting flange 118 b bent from an inboardend of the cylindrical portion 118 a so as to extend radially outwardly.The mounting collar 118 b is formed with a bolt insertion hole forpassage therethrough of a bolt 119 used to secure the outer member 102to the knuckle 110 and is held against the end face of the outer membermount 110 a of the knuckle 110. When the outer member 102 is bolted tothe knuckle 110 by means of the bolt 119 with the mounting flange 118 btherefore clamped between the bolt 119 and the outer member mount 110 a,the support plate 118 is rigidly secured to the knuckle 110. Thus, themagnetic ring assembly 113 is fitted to the knuckle 110 through thesupport plate 118 with the outer periphery of the magnetic ring assembly113 press-fitted in the inner periphery of the cylindrical portion 118 aof the support plate 118.

An outboard end of the cylindrical portion 118 a of the support plate118 has a radially inwardly extending flange 118 c formed by bending itso as to extend radially inwardly therefrom. This radially inwardlyextending flange 118 c is held in contact with one end face of themagnetic ring assembly 113 so that the magnetic ring assembly 113 can beaxially retained in position. The inner peripheral surface of the outermember mount 110 a of the knuckle 110 represents a stepped cylindricalsurface with a portion thereof, adjacent the mounting flange 118 b ofthe support plate 118, flaring radially outwardly in a direction awayfrom the electric power generator 111, thereby leaving a reduced innerdiameter portion and a large inner diameter portion. The cylindricalportion 118 a of the support plate 118 is correspondingly stepped tohave a reduced diameter portion, engaged around the reduced innerdiameter portion of the outer member mount 110 a, and a large diameterportion engaged around the large inner diameter portion of the outermember mount 110 a. An elastic sealing element 121 is clamped between astep 110 aa of the inner peripheral surface of the outer member mount110 a and a step 118 aa of the cylindrical portion 118 a of the supportplate 118, to thereby seal an axial gap between the inner peripheralsurface of the outer member mount 110 a and the cylindrical portion 118a of the support plate 118. The elastic sealing element 121 is of a ringshape and may be, for example, an O-ring.

In the wheel support bearing assembly of the structure discussed above,the magnetic ring assembly 113 employed therein is of the structureshown in and described with reference to FIG. 4 and, therefore, thedetails thereof are not reiterated for the sake of brevity.

As shown in FIG. 28, the magnetic ring assembly 113 defining the yoke ofthe electric power generator 111 has a hollow in which a coil 125 woundaround a coil bobbin 124 and an electric circuit 126 of the wirelesstransmission device 120 are accommodated.

While the electric circuit 126 of the wireless transmission device 120is similar to that shown in the circuit block diagram of FIG. 16 and,accordingly, the details thereof are not reiterated for the sake ofbrevity, the transmitting antenna 244 (FIG. 16) of the wirelesstransmission device 120 is mounted on an outer periphery of the reduceddiameter portion of the ferromagnetic ring member 30 c that protrudesfrom one end of the magnetic ring assembly 12, shown in FIG. 25, towardsthe inboard side and is resin molded by a resin filler 127 as shown inFIG. 28. The electric circuit 66 inside the magnetic ring assembly 113and the transmitting antenna 244, both shown in FIG. 16, areelectrically connected with each other by means of a wiring passingthrough a wiring hole defined in one side wall of the magnetic ringassembly 113 so as to extend completely across the thickness thereof. Itis to be noted that a circuit portion of the electric circuit 66 may bepositioned outside the magnetic ring assembly 113 together with thetransmitting antenna 244.

Referring now to FIG. 28, the multi-pole magnet assembly 112 is made upof a multi-pole magnet member 128 and an annular core metal 129. Themagnet member 128 is, for example, a rubber magnet and is bonded byvulcanization to the core metal 129. Where the core metal 129 isemployed, the core metal 129 is preferably made of a magnetic material,particularly a ferromagnetic material. The core metal 129 may be in theform of either an annular member of a generally L-shaped section asshown in FIG. 30 or an annular member of a generally U-shaped section.The annular core metal 129 is fixed in potion as press-fitted on theouter peripheral surface of the inner member 103. The multi-pole magnetassembly 112 may be either a plastic magnet or a sintered magnet and maybe bonded to the outer peripheral surface of the inner member 103 by theuse of, for example, a bonding agent. Where the multi-pole magnetassembly 112 is employed in the form of the plastic magnet or thesintered magnet, the use of the core metal 129 may be dispensed with.

A sealing member 147 is mounted inside the reduced diameter portion ofthe ferromagnetic ring member 130 c forming a part of the magnetic ringassembly 113. This sealing member 147 is of a structure including a coremetal 148 of a generally L-shaped section bonded and, hence, integratedtogether with a sealing element 149 made of an elastic material. Thesealing element 149 has a plurality of elastic lips. Although the numberof the elastic lips forming the sealing element 149 may be suitablychosen, the sealing element 149 so far shown includes a single radiallip 150 a and two side lips 150 b. A slinger 151 made of a stainlesssteel and defining a seal contact area is provided in a shoulder of theouter race 115 a of the constant velocity universal joint 115 so as toconfront the sealing member 147. The inboard sealing member 147 and theoutboard sealing member 109 (See FIG. 27) cooperate with each other toprevent external saline dirt and grits from entering the annular workingspace between the outer and inner members 102 and 103.

The slinger 151 is of a generally L-shaped section having a radiallyextending flange that terminates at a location adjacent a radially outerbase end of the sealing member 147 to define a slight gap between it andthe radially outer base end of the sealing member 147 to thereby form anon-contact seal 153. By so designing, the sealability can be increasedadvantageously.

The radially inwardly extending flange 118 c of the support plate 118 isheld in contact with the annular end face of the outer member 102 andextends radially inwardly beyond the inner peripheral surface of theouter member 102. A generally ring-shaped sealing plate 152 positionedaxially inwardly of and spaced a slight distance from the radiallyinwardly extending flange 118 c is mounted on the outer periphery of theinner member 103 so that the sealing plate 152 can cooperate with theradially inwardly extending flange 118 c to define a labyrinth seal 159.The sealing plate 152 is of a generally L-shaped section having acylindrical portion that is mounted on the outer peripheral surface ofthe inner member 103. By this labyrinth seal 159, any possible leakageof a grease filled in the bearing assembly can be avoidedadvantageously.

The outer race 115 a of the constant velocity universal joint 115 is, inorder to secure a required thickness, formed with a curved surfaceportion 115 aa following a fillet surface, formed on an inner raceforming member 103B forming a part of the inner member 103, that extendsradially inwardly from the inboard end to the inner periphery of theinner race forming member 103B, and a tapering portion 115 ab continuedfrom the curved surface portion 115 aa to the shank 116.

The operation of the bearing assembly of the structure described abovewill now be described. A portion of the electric power generated by theelectric power generator 111 is supplied to the electric circuit 126disposed inside the magnetic ring assembly 113 and is subsequentlyprocessed by the signal processing circuit 240 in FIG. 16 to provide therotational speed detection signal indicative of the number ofrevolutions of the wheel. The electric power generated by the electricpower generator 111 is also supplied to the electric power sourcecircuit 243 in which it is rectified and smoothed to provide an electricpower source for the signal processing circuit 240 and the transmittercircuit 242. The resultant rotational speed detection signal istransmitted wireless as a radio wave from the transmitter circuit 242 tothe receiver circuit 253 through the transmitting antenna 244.

In the wheel support bearing assembly of the type equipped with theelectric power generator as discussed above, since the magnetic ringassembly 113 of the electric power generator 111 is mounted on theknuckle 110 and the multi-pole magnet assembly 112 is mounted on theinner member 103, the electric power generator 111 can be effectivelyand efficiently incorporated in a relatively small space left on theinboard side of the bearing assembly, resulting in increase of thefreedom of design choice. In particular, since the end face of the outermember 102 is set back axially inwardly relative to the end face of theinner member 103 with the magnetic ring assembly 113 of the electricpower generator 111 arranged within the space created by the set-back, arelatively large space is available for installation of the electricpower generator 111. Also, since the amount of material used toconstruct the outer member 102 can advantageously be reduced in aquantity corresponding to a portion of the outer member 102 that hasbeen set back axially inwardly, the cost of material can also bereduced.

Also, considering that the support plate 118 is fitted to the knuckle110 by means of the bolt 119 used to bolt the outer member 102 to theknuckle 110 and the magnetic ring assembly 113 of the electric powergenerator 111 is mounted on the inner peripheral surface of thecylindrical portion 118 a defined in the support plate 118, mounting ofthe magnetic ring assembly 113 can easily be accomplished. Also, sincethe provision of the radially inwardly extending flange 118 c in thesupport plate 118 is effective to define the labyrinth seal 159 betweenit and the sealing plate 152 on the outer periphery of the inner member103, an effect of preventing the grease from leaking can be obtainedwith a minimized number of component parts.

In addition, since the slinger 151 is disposed on an inboard side of theportion of the inner member 103 where the multi-pole magnet assembly 112is mounted and the sealing member 147 slidably engageable with theslinger 151 is mounted on the magnetic ring assembly 113, the sealingwithin the bearing assembly and the protection of the multi-pole magnetassembly 112 of the electric power generator 111 can both be achieved bythe common sealing member 147. Formation of the non-contact seal 153between the sealing member 147 and a free end of the slinger 151 iseffective to increase the sealability. Also, since the elastic sealingelement 121 is interposed in the area where the stepped cylindricalportion 118 a of the support plate 118 is mounted on the knuckle 110,the sealing at this area can be secured.

FIG. 29 illustrates a still further preferred embodiment of the presentinvention. The embodiment of FIG. 29 is similar to that shown in anddescribed with reference to FIGS. 26 to 28, except that the cylindricalportion 118 a of the support plate 118 employed in the embodiment ofFIG. 29 has no step and, instead, a resin layer 154 is formed on anouter peripheral surface of the cylindrical portion 118 a. By causingthe resin layer 154 to be mounted on the large diameter portion of thestepped cylindrical portion of the outer member mount 110 a in theknuckle 110, a seal can be achieved between the inner peripheral surfaceof the knuckle 110 and the cylindrical portion 118 a of the supportplate 118. Other structural features than those described above aresimilar to those in the previously described embodiment and, therefore,the details thereof are not reiterated for the sake of brevity.

In the case of the embodiment shown in FIG. 29, the seal can be achievedbetween the knuckle 110 and the cylindrical portion 118 a of the supportplate 118 with no need to use the elastic seal 121 such as an O-ring,the number of component parts employed can be reduced advantageously andassemblage can also be easily accomplished.

FIG. 30 illustrates a still further preferred embodiment of the presentinvention. This embodiment is similar to that shown in and describedwith reference to FIGS. 26 to 28, except that one end of theferromagnetic ring member 130 a forming a part of the magnetic ringassembly 113 has an extension to define the support plate 118. Otherstructural features than those described above are similar to those inthe previously described embodiment and, therefore, the details thereofare not reiterated for the sake of brevity.

According to the embodiment shown in FIG. 30, since the support plate118 is an integral part of the ferromagnetic ring member 130 a forming apart of the magnetic ring assembly 113, the electric power generator 111can be inexpensively constructed with a minimized number of componentparts. In such case, a portion of the magnetic ring assembly 113 isexposed to the outside of the bearing assembly and, therefore, amaterial having an excellent water proofing property, such as astainless steel is employed as a material for the magnetic ring assembly113.

FIG. 31 also illustrates a still further preferred embodiment of thepresent invention. This embodiment of FIG. 31 is similar to theembodiment shown in and described with reference to FIGS. 26 to 28,except that the core metal 129 of the multi-pole magnet assembly 112 isof a generally stepped cylindrical configuration having a large diameterportion and a reduced diameter portion continued axially inwardlytherefrom with the large diameter portion held in contact with the outerperipheral surface of the inner member 103 and also with the reduceddiameter portion engaged with the shoulder of the outer race 115 a ofthe constant velocity universal joint 115, while an annular step 129 aof the core metal 129 is held in abutment with the annular end face ofthe inner race forming member 103B. The magnet member 128 is bonded byvulcanization to an outer peripheral surface of the reduced diameterportion of the core metal 129. Other structural feature than thosedescribed are similar to those in the previously described embodimentand, therefore, the details thereof are not reiterated for the sake ofbrevity.

According to the embodiment shown in FIG. 31, the inner member 103 canhave its axial length reduced by a quantity corresponding to the spaceoccupied by the multi-pole magnet assembly 112. Accordingly, the outerrace 115 a of the constant velocity universal joint 115 can have anincreased axial length by a quantity equal to the reduction in the axiallength of the inner member 103 and, therefore, the outer race 15 a canhave an increased wall thickness.

A yet further preferred embodiment of the present invention is shown inFIG. 32. The embodiment shown therein is similar to the embodiment shownin FIG. 30, in which a constituent member 130 a of the magnetic ringassembly 113 and the support plate 118 are integrated together. However,the embodiment of FIG. 32 differs from the embodiment of FIG. 30, inthat the core metal 129 of the multi-pole magnet assembly 112 is mountedso as to straddle between the inert member 103 and the outer race 115 aof the constant velocity universal joint 115 as is the case with theembodiment shown in and described with reference to FIG. 31. Except forthis difference, other structural feature than those described aresimilar to those in the previously described embodiment and, therefore,the details thereof are not reiterated for the sake of brevity.

According to the embodiment of FIG. 32, not only can the number ofcomponent parts used be reduced advantageously, but also the electricpower generator 111 can be inexpensively manufactured, and also theouter race 115 a can have an increased wall thickness.

FIG. 33 illustrates a yet further preferred embodiment of the presentinvention. This embodiment of FIG. 33 is similar to that shown in anddescribed with reference to FIGS. 26 to 28, except that the electricpower generator 111A employed in this embodiment of FIG. 33 is of anaxial type. Specifically, the multi-pole magnet assembly 112 mounted onthe inner member 103 is so disposed as to permit a magnetized surfacehaving the alternating magnetic poles N and S to confront in a directionaxially of the bearing assembly. The magnetic ring assembly 113 mountedon the knuckle 110 is so disposed as to axially confront the magnetizedsurface of the multi-pole magnet assembly 112. The comb-shaped claws 31a and 31 b (FIG. 4B) of the magnetic ring assembly 113 are formed on aside surface confronting the multi-pole magnet assembly 112. Also, theradially inwardly extending flange 118 c of the support plate 118 hassuch a short length that it will not cover the claws 31 a and 31 b ofthe magnetic ring assembly 113. The sealing plate 152 in FIG. 26 isdispensed with. Other structural features than those described above aresimilar to those used in the previously described embodiment and,therefore, the details thereof are not reiterated for the sake ofbrevity.

According to the embodiment shown in and described with reference toFIG. 33, since the electric power generator 111 is so designed as to bean axial type, the mounting space, that is, the axial size of the spacein which the multi-pole magnet assembly 112 is mounted on the innermember 103 can be reduced and, correspondingly the axial length of theouter race 115 a of the constant velocity universal joint can beincreased advantageously to permit the outer race 115 a to have anincreased wall thickness. Also, in view of the axial type, themulti-pole magnet assembly 112 assumes a radially extending shape and,as is the case with the sealing plate 152 used in the previouslydescribed embodiment, the multi-pole magnet assembly 112 has a role ofdefining a labyrinth seal for prevention of leakage of the grease.Because of this, the use of the sealing plate 152 can advantageously bedispensed with, resulting in inexpensive manufacture of the wheelsupport bearing assembly with the reduced member of components parts andmanufacturing steps.

FIG. 34 illustrates a still further preferred embodiment of the presentinvention. This embodiment of FIG. 34 is similar to the axial typeembodiment shown in and described with reference to FIG. 33, except thatthe ferromagnetic ring member 130 a forming a part of the magnetic ringassembly 113 has one end extended to provide an extension that in turndefines the support plate 118. Other structural feature than thosedescribed above are similar to those in the previously describedembodiment and, therefore, the details thereof are not reiterated forthe sake of brevity.

In the embodiment of FIG. 34, since the extension and, hence, thesupport plate 118 is an integral part of the ferromagnetic ring member130 a forming a part of the magnetic ring assembly 113, the number ofcomponent parts can advantageously be reduced and the electric powergenerator 111A can be assembled inexpensively.

FIG. 35 illustrates a still further preferred embodiment of the presentinvention. This embodiment of FIG. 34 is similar to the embodiment shownin and described with reference to FIGS. 26 to 28, but differs therefromin that the multi-pole magnet assembly 112 in its entirety is mounted onthe shoulder of the outer race 115 a of the constant velocity universaljoint. The core metal 129 of the multi-pole magnet assembly 112 usedtherein has one end extended towards the inboard side to define anextension that in turn forms the slinger 151 defining a seal contactmember. It is to be noted that the outer race 115 a of the constantvelocity universal joint 115 is firmly connected with the inner member103 when the nut 117 is firmly fastened to the shank 116 as shown inFIG. 27, but a contact pressure is developed between an end face 103 cof the inner race forming member 103B defining the inner member 103 andan end face 115 ac of the shoulder of the outer race 115 a confrontingtherewith, thus requiring a contact surface area therebetween. In viewof this, in the embodiment of FIG. 34, the curvature of an angledportion 103 d varying radially inwardly from the end face 103 c of theinner race forming member 103B has its radius reduced for the purpose ofsecuring the contact surface area between the end face 103 c of theinner race forming member 103B defining the inner member 103 and the endface 115 ac of the shoulder of the outer race 115 a. Other structuralfeatures than those described above are similar to those in thepreviously described embodiment and, therefore, the details thereof arenot reiterated for the sake of brevity.

According to the embodiment shown in FIG. 35, since the extension and,hence, the slinger 151 is an integral part of the core metal 129 of themulti-pole magnet assembly 112, the number of the component parts usedand the number of manufacturing steps can be reduced advantageously,allowing the wheel support bearing assembly to be manufacturedinexpensive.

FIG. 36 illustrates a still further preferred embodiment of the presentinvention. This embodiment of FIG. 36 is similar to the embodiment ofFIG. 35 in which the slinger 151 is an integral part of the core metal129 of the multi-pole magnet assembly 112, but differs therefrom in thatthe ferromagnetic ring member 130 a forming a part of the magnetic ringassembly 113 has one end extended to form an extension which thendefines the support plate 118. Other structural features than thosedescribed above are similar to those in the previously describedembodiment and, therefore, the details thereof are not reiterated forthe sake of brevity.

According to the embodiment of FIG. 36, not only since the slinger 151is an integral part of the core metal 129 of the multi-pole magnetassembly 112, but also since the magnetic ring assembly 113 and thesupport plate 118 are integrated together, the number of the componentparts used and the number of manufacturing steps can be reducedadvantageously, allowing the wheel support bearing assembly to bemanufactured inexpensive.

Yet a still further preferred embodiment of the present invention isshown in FIG. 37. This embodiment of FIG. 37 is similar to theembodiment shown in and described with reference to FIGS. 26 to 28, butdiffers therefrom in that a rotation detecting sensor 155 is providedinside the magnetic ring assembly 113 of the electric power generator111. This rotation detecting sensor 155 is comprised of a Hall elementor the like. In this case, the sensor 155 detects the rotational speeddetection signal in terms of change in polarity of the multi-pole magnetassembly 112 resulting from rotation of the wheel, which signal istransmitted wireless by the wireless transmission device 120 as a radiowave. The electric power generated by the electric power generator 111is used as an electric power source for the rotation detecting sensor155 and the wireless transmission device 120. It is to be noted that therotation detecting sensor 155 referred to above may not always detectonly the rotational speed, but may detect any other parameter such asvibrations and/or temperature. Also, the position of the rotationdetecting sensor 155 may not be always limited to the inside of themagnetic ring assembly 113, but may be disposed in the outer member 102or the knuckle 110.

Although in describing any one of the foregoing embodiments the outerrace 115 a of the constant velocity universal joint 115 has beendescribed as a member separate from the inner member 103 and, hence, hasbeen described as mounted on the inner member 103, the wheel supportbearing assembly according to a broad aspect of the present inventionmay be of a structure in which the outer race 115 a of the constantvelocity universal joint 115 forms an element that defines a part of theinner member 103 and, therefore, one or more inner raceways 106 b may bedefined in such outer race 115 a.

Although the present invention has been fully described in connectionwith the preferred embodiments thereof with reference to theaccompanying drawings which are used only for the purpose ofillustration, those skilled in the art will readily conceive numerouschanges and modifications within the framework of obviousness upon thereading of the specification herein presented of the present invention.Accordingly, such changes and modifications are, unless they depart fromthe scope of the present invention as delivered from the claims annexedhereto, to be construed as included therein.

1. A rotation detecting device which comprises: a rotatable memberrotatably supported on a non-rotatable member; an electric powergenerator for generating an electric power by a relative rotationbetween the non-rotatable member and the rotatable member; atransmission device for transmitting wireless at least one of arotational speed detection signal outputted by the electric powergenerator and an output signal from a sensor that operates using as anelectric power source the electric power generated by the electric powergenerator, said transmission device being of an annular configuration;and a sealing member for sealing a space delimited between thenon-rotatable member and the rotatable member; said electric powergenerator comprising a multi-pole magnet assembly having a plurality ofalternating magnetic poles arranged in a circumferential direction, anda magnetic ring assembly accommodating a coil and confronting themulti-pole magnet assembly; said wireless transmission device beingdisposed axially outwardly, but adjacent to the magnetic ring assemblyof the electric power generator; said sealing member being mounted onthe wireless transmission device and having a lip member slidinglyengaged with a seal contact area defined in the rotatable member; andsaid magnetic ring assembly and the multi-pole magnet assembly of theelectric power generator confronting with each other at a locationinwardly of the sealing member.
 2. A rotation detecting device whichcomprises: a rotatable member rotatably supported on a non-rotatablemember; an electric power generator for generating an electric power bya relative rotation between the non-rotatable member and the rotatablemember; a transmission device for transmitting wireless at least one ofa rotational speed detection signal outputted by the electric powergenerator and an output signal from a sensor that operates using as anelectric power source the electric power generated by the electric powergenerator, said transmission device being of an annular configuration;and a sealing member for sealing a space delimited between thenon-rotatable member and the rotatable member; said electric powergenerator comprising a multi-pole magnet assembly having a plurality ofalternating magnetic poles arranged in a circumferential direction, anda magnetic ring assembly accommodating a coil and confronting themulti-pole magnet assembly; said wireless transmission device beingintegrated together with the magnetic ring assembly; said sealing memberbeing mounted on the wireless transmission device and having a lipmember slidingly engaged with a seal contact area defined in therotatable member; and said magnetic ring assembly and the multi-polemagnet assembly of the electric power generator confronting with eachother at a location inwardly of the sealing member.
 3. A rotationdetecting device which comprises: a rotatable member rotatably supportedon a non-rotatable member; an electric power generator for generating anelectric power by a relative rotation between the non-rotatable memberand the rotatable member; a transmission device for transmittingwireless at least one of a rotational speed detection signal outputtedby the electric power generator and an output signal from a sensor thatoperates using as an electric power source the electric power generatedby the electric power generator, said transmission device being of anannular configuration; and a sealing member for sealing a spacedelimited between the non-rotatable member and the rotatable member;said electric power generator comprising a multi-pole magnet assemblyhaving a plurality of alternating magnetic poles arranged in acircumferential direction, and a magnetic ring assembly accommodating acoil and confronting the multi-pole magnet assembly; said wirelesstransmission device being mounted on the non-rotatable member; saidsealing member being mounted on the wireless transmission device andhaving a lip member slidingly engaged with a seal contact area definedin the rotatable member; and said magnetic ring assembly and themulti-pole magnet assembly of the electric power generator confrontingwith each other at a location inwardly of the sealing member.
 4. Therotation detecting device as claimed in claim 1, wherein the wirelesstransmission device has an inner peripheral surface formed with ato-be-engaged portion comprised of a projection or a recess and thesealing member is formed with an engaging portion comprised of a recessor a projection engageable with the to-be-engaged portion on the innerperipheral surface of the wireless transmission device, said sealingmember being mounted on the inner peripheral surface of the wirelesstransmission device with the engaging portion engaged with theto-be-engaged portion.
 5. A rotation detecting device which comprises: arotatable member rotatably supported on a non-rotatable member; anelectric power generator for generating an electric power by a relativerotation between the non-rotatable member and the rotatable member; atransmission device for transmitting wireless at least one of arotational speed detection signal outputted by the electric powergenerator and an output signal from a sensor that operates using as anelectric power source the electric power generated by the electric powergenerator; and a sealing member for sealing a space delimited betweenthe non-rotatable member and the rotatable member; said electric powergenerator comprising a multi-pole magnet assembly having a plurality ofalternating magnetic poles arranged in a circumferential direction, anda magnetic ring assembly accommodating a coil and confronting themulti-pole magnet assembly; said sealing member being mounted on aninner peripheral surface of the magnetic ring assembly and having a lipmember slidingly engaged with a seal contact area defined in therotatable member; and said magnetic ring assembly and the multi-polemagnet assembly of the electric power generator confronting with eachother at a location inwardly of the sealing member.
 6. The rotationdetecting device as claimed in claim 5, wherein the inner peripheralsurface of the magnetic ring assembly of the electric power generator isformed with a to-be-engaged portion comprised of a projection or arecess and the sealing member is formed with an engaging portioncomprised of a recess or a projection and engageable with theto-be-engaged portion on the inner peripheral surface of the magneticring assembly, said sealing member being mounted on the inner peripheralsurface of the magnetic ring assembly with the engaging portion engagedwith the to-be-engaged portion.